All I can do is apologise for such a huge delay, but eventually this chapter came together - hopefully you guys will enjoy it!

Oddly enough, an opportunity came sooner than I'd expected, and from a rather different source than mentally predicted.

Life in the Tower had gradually become slightly dull. Not that I didn't appreciate every free moment, but it was deciding how to spend it that made the moment fall a little flat. The fact that the place seemed practically empty half the time didn't help; Tony had mentioned something about "covert operations" over that morning's breakfast, winked, and then refused to say another word. Barton and Natasha were equally secretive, although Steve briefly explained that they were full time SHIELD agents with some assassin work on the side.

Strangely, 'assassin' was a word that seemed surprisingly familiar, considering that Tony had previously been forced to explain what half of the kitchen appliances were for before I could break anything.

This not only explained their continual absence, and a certain harried look whenever they happened to be present, but also the slightly brittle atmosphere they carried about them, as if the air might crack in two. Well, at least that was the impression Natasha left in her wake; Clint was far more relaxed, and had even given me a go on the indoor shooting range. It had been fairly simple to pick up, even enjoyable, and after the first few shots I was quickly splitting arrows, which for some reason had turned Clint's face a sort of chalky colour. I wasn't quite sure if that was a reaction to my skill, or the highly expensive arrows which I was steadily snapping before his eyes.

He hadn't invited me back.

So, for the most part, I was stranded by myself. When I decided to take a stroll – because Stark Tower was big enough to go for a walk and come back footsore and more than a little lost – I rarely caught a glimpse of a familiar face, although there were plenty of alien ones passing through daily. Anonymous men in black suits with thunder-coloured eyes and flat mouths to match regarded me out of the corners of their eyes with something akin to alarm. Upon wishing one a good morning, he'd instantly strode into the nearest office and slammed the door.

People were so refreshingly cheerful.

Thankfully, Steve tended to show up in the evenings, a little worn about the edges from whatever task Fury had set him, but always ready with a smile and a card game, or a new book to loan me. Unfortunately, I tore through them faster than he was able to procure them. I could get through one in under a day easily, in a couple of hours if I really pushed it, and yet could still repeat the first five or so chapters with barely a hesitation for breath; the look of shock on Tony's face when I'd greeted him in the morning with the first three pages of Macbeth had been priceless.

Quiet days in which to amuse myself, and then evenings in which people gradually began to filter back into the surroundings in the same way that bees return to the hive. This seemed to become something of a routine which I quickly acclimatised to. It was... nice. I couldn't think of any other way in which to describe the sensation of knowing where the day was going, and how tomorrow would comfortably follow along those same well-oiled rails. Life lazily ambled by, and time burned a considerable hole through its pocket; I had ample hours at my disposal, and yet seemingly little to spend them on.

However, today broke the pattern. It was the middle of the day when the siren call of the city was at its strongest, the blue sky simply too bright to ignore. I was like a moth to a flame. I'd spent a little time in the gym, at a loss for anything else to do, and then had settled down with the intention of reading. Yet the book lay forgotten in my lap as I gazed skywards at the fluted clouds that rumbled across the endless plains of the sky, leaving nothing but tiny smeared puffs of dust in their wake. The lazy lap and tug of the sunshine washed the buildings clean and pooled warmly about my ankles. I couldn't even remember what I'd been reading; perhaps it had been something about time-travel. Those seemed to be Steve's favourite.

"Good book?" I turned to see Bruce hovering, a little nervously, in the doorway. I could barely see his face in the shallow gloom after the blinding brightness of the window.

I made a non-committal noise, and got up, groaning at the stiffness in my legs. I must have been sitting there for ages; even now I moved away from the window with a certain measure of reluctance. I tossed the book onto the bed in a sudden gesture of defeat.

"You don't have to get up, I-"

"No, it's fine." I smiled. "I needed to really. Another few minutes and the glass would probably start to crack." A thin frost of scratches had already begun to grow around the frames. Nothing serious considering the thickness of the glass – the doors of the laboratory seemed like wet paper in comparison – but still a visible reminder of my knack for causing damage. Hopefully Tony wouldn't notice.

Bruce smiled gently, not even attempting to talk. In a way, I preferred the silence, the friendly atmosphere to the many-layered deceit of words. He seemed especially good at communicating through pauses; simple actions such as the downcasting of his eyes, or a furtive smile, seemed to display a multitude of different meanings that I struggled to understand.

"I assumed you were out; Tony said he had some sort of errand to run." Errand probably wasn't quite the right word; only trouble was I had no idea which one was.

He scratched the back of his neck sheepishly. "I'm something of a ticking time bomb. I'm not exactly the best person to take into the field." He picked up the book, and examined the cover. "Plus, Tony needed someone back at the lab to process any data he might send through."

"What data?"

"I'm not really-"

"Meant to tell me?" I guessed brightly.

"Basically. So long as Fury doesn't get wind of it..."

"Oh?" This sounded good all of a sudden. The sun-soaked glass lay forgotten behind me.

He chuckled. "I thought that might interest you."

"Watching Tony get himself into trouble is always amusing."

He smirked. "The novelty wears off fast. If it helps, we've got nothing so far. Or at least I haven't, goodness knows what Tony's doing-"

"But what is he doing?"

Bruce narrowed his eyes, gauging my reaction, or perhaps weighing in his mind what my reaction might be. "From what I can tell, he's been digging around the NYBU, asking a few questions. He has a knack at worming his way into places he shouldn't be."

"The NY... My lab?" I internally winced at the use of 'my'. It wasn't mine, it would never be. And yet it seemed to be my only proper connection to the world, as much as I reviled it. I much preferred the one I was slowly but surely building here.

"Come on - human experimentation? Something smelt a bit funky. At least that's what Tony said."

I shrugged. "Who wouldn't? I mean, look how I turned out."

"Ha ha." He couldn't have sounded less amused if he'd just witnessed a brutal murder. "But this is all technically off the books. Really we're breaking quite a few rules, and severely bending the rest." He smiled tersely. "Hence my lack of direct involvement. A rather more stress-free environment, don't you think?"

"Depends if stress-free is a synonym for boring."

His smile softened and warmed. "How did you guess?"

"Mostly experience," I grumbled. Part of me wondered if any of the others had a hand in these investigations, if that was where Steve went during the day. Then again, was there really that much to investigate? There was just... me. I most likely had by origins in a drunken bet or science fiction story, of which I'd now read quite a few.

"If you haven't got anything to do, I'd be grateful if I could get some extra readings... I mean, Tony got some remarkable brain patterns when you were in the cube, and I'd be interested to run a few more tests-" Bruce began to earnestly polish his glasses on the hem of his shirt. His skin shimmered with a barely noticeable whiff of hesitation.

Uh oh. I tried to squash down the flare of dread in my stomach. "What, you want a demo?" I shrugged with assumed nonchalance, but inside my guts were twisting and writhing into one another like a nest of snakes. Big, venomous snakes. Snakes that hadn't eaten in weeks.

"Yes!" He looked relieved. "Only if that's-"

I hesitantly nodded my agreement, a little too embarrassed to refuse his request. He meant well, I could smell that straight off, and the blazing apology in his eyes when we'd first met had been genuine. Even so, I couldn't help but feel some trepidation as I followed the doctor down two flights of stairs, took a right, a left, two rights, then stopped before a door. What sort of tests?

Bruce pushed it open. The first thing that hit me was the stench of chemicals, antiseptic, a bitter lime quality to the air I breathed that was enough to flip my stomach. Everything gleamed a cold white, the chill creeping under my skin to fill the space where the embrace of sunlight had just been.

"Are you okay?" Banner looked concerned, and I realised that he'd noticed the sudden wheezing of my lungs as I struggled for breath. The air wore the heavy translucence of glass. I forced a smile, hurriedly perching on a lab stool before my knees gave way. It's fine. "I'm fine. Honestly."

"You've gone rather pale." He followed my wary gaze to the racks of nameless instruments, the painful glint of steel, and realisation clicked into place with the speed of a lightning bolt. "I'm so sorry, and I call myself a doctor. I should have realised that bringing you here of all places would be a bad idea-"

"No, really, I'm fine, I just..." I tugged at the collar of my shirt, suddenly feverish. Every breath scraped sharply at the back of my throat, so cold, so dry. "I'm having a little trouble..." My eyes hurt from the glint of metal, the bright white glare piercing my skin like burning needles. A lump grew in my throat, and I gagged, tasted the bile, the blood-

Then arms were around my shoulders, guiding me forwards firmly, catching my elbow when my foot slipped. The white haze dimmed and fell, buzzing black spots rushing in to cluster where the light had been. Somehow I'd moved into a smaller, darker room, what looked to be an office of some sort with a desk and a few plush chairs scattered about. Banner sat across from me, eyes dark with worry. "Give yourself a minute," he said.

"What happened?" I asked weakly. There was a dim ring in my ears, and I was grateful for the sudden darkness that enveloped us both. He must have shut the curtains.

"The lab must have triggered a memory, or a panic response." He sighed. "I was a fool not to have seen it coming."

"Sorry, what sort of doctor are you again?"

The corner of his mouth twitched wryly. "Mostly science, with some medicine thrown in."

I passed a hand over my face wearily. If anything I was more ashamed of my sudden weakness than afraid. I'd lost count of the number of times I'd fainted since arriving; they must have been getting rather tired of it. "Glad to know I'm in good hands."

"Oh, the best!" His voice carried an undertone of sarcasm, but it was softly directed to brighten the mood.

I suddenly felt bad for having reacted so dramatically. Whilst Banner was a scientist, he wasn't like Winters who almost acted out of malice. I suddenly wanted to show him what I could do. In a way, he deserved that much.

"Go on then, you wanted this demonstration-" I stood up, but then quickly sat down again at the sudden instability of my legs. "Thinking better of it, I could probably do it sitting down."

Bruce frowned. "I don't think that would be wise. Honestly, I was hoping for some readings on heart rate and blood pressure to see how they'd match the brain signals Tony had already collected, but..." He sighed, eyes brimming with apology.

"No needles?"

"Not so much as a pin."

"Well, a pin might be necessary." I'd caught sight of a box of thumb tacks on the desk, and with a here-goes-nothing attitude snatched one up. Before Banner could protest, I sank it into the soft part of my thumb.

"Ah!" A chair was thrown sideways, leg crumpled into a useless mass of metal beneath it. The pin shot up like a rocket, pinging off the ceiling and landing in the waste paper basket with an artistic flourish. I sucked at the wound it had left. Those things were sharper than they looked. "Good enough, Doc?"

Bruce picked up the chair, ran a finger over the mutilated metal, and then gazed at me, eyebrows raised. I flinched as his eyes met mine, but they weren't bright with horror or disgust, but amazement. "I've never... How?"

I scrunched my mouth up as I thought. "I don't really know."

"And what, the pain is a... a trigger?"

"Something like that. It just sort of happens when I'm hurt, or threatened." I grimaced. "I can't really aim it, if you know what I mean."

"So it could have easily been the desk that got trashed instead."

"Or the window. Or maybe that pencil lying there." I gave him a level stare. "Or you."

He returned my gaze, nonplussed. Or at least if he was bothered, his face remained unruffled. This was a man who kept his emotions in check.

I tried again. "I did it once before. A guy tasered me, and I broke his hand."

"Did you mean to?"

"No. At least, I don't think so."

Bruce shifted in his seat. "It seems like it probably acts as a defence mechanism, a little like white blood cells. The tissue is threatened, so the body does what it can to fight off the threat." He mused softly to himself, seemingly in some sort of hazy dream that I was barred access to. "Now, if you were able to gain control of that..."

I eyed the twisted chair uneasily, imagining for a second that it was a human limb, a shattered arm, a bone squeezed into an agonising shape of my own design. More than anything I didn't want to possess that power.

"Maybe..." Bruce hesitated, hovering on the edge of his seat with palpable excitement. "Do you respond to emotional pain too?"

"Umm..." I hadn't actually contemplated that possibility before.

"Or what about the memory of pain? So if you were to replay the sensation of the pin, but in your mind...?"

"Again, not a clue!" I smiled apologetically; he had so many questions, and oddly I felt as though I ought to supply a response. The way in which he asked was odd, both probing and yet delicate, wary, leaving me space in which to back away should I wish to. He cared. I wasn't quite sure why that surprised me; of everyone I'd met so far, his scent had been the subtlest and least obtrusive. Even unconsciously he sought to remain unnoticed. "I wish I had answers, but I don't even think the NYBU has a clue."

"So, what, your powers were some sort of-"

"Mistake?" I wiped my hands on my jeans, voice heavy with something bitter that I hoped he couldn't hear. "That about sums it up. I guess that's what about sums me up." I regretted the words the moment I spoke them; I couldn't have sounded more self-pitying if I'd tried. I kept my eyes fixed on my hands, the creases of my knuckles, nails scratching over the dirty bandage that had almost become part of my hand, anything but his face.

I heard him sigh, and a rustle, maybe as he adjusted himself in his seat. Then his hand hesitantly brushed mine. The contact was brief, but enough to freeze me in my seat.

"You're not a mistake," he said softly.

I raised my eyes to meet his. For some odd reason, a laugh bubbled up from the back of my throat. My whole situation was just so weird it was almost hysterical. Here I was, having a heart-to-heart with a doctor who happened to turn into a giant green rage monster in his spare time.

"Believe me," he added. "I know a lot about mistakes." He sat back, and amusement ghosted over his face. "Why don't you take off your bandage?"

I eyed him with some suspicion, but obeyed, unwrapping the fabric from around my hand. It had once been white, and was now a dirty yellow; I'd grown so accustomed to its presence that I'd forgotten I'd even been wearing it. As I gazed down at the freshly unveiled skin, I couldn't even recalled why I'd needed it. My palm was flawless. Unscarred.

"That probably could have been taken off ages ago," Banner grinned. "When they first brought you in, I was told to examine the wound. It was a deep incision; I thought that you'd need stitches, but by the time I was called in, the wound had stopped bleeding, and was already beginning to scab on its own."

I flexed my hand in wonder. Judging from the tone of awe in his voice, that wasn't normal.

"Still feeling like a mistake?"

A smile involuntarily pulled my lips out of shape. "Why, what would you call it?"

He stood. "At a push, a miracle."

He offered me a hand up, but I didn't need it now that my legs were back under control. "Aren't miracles and mistakes basically the same thing?"

Banner adjusted his glasses, and smirked. "I feel like I've just been Tony-ed."

"You know, Tony says that all the time," I said airily.

"I wouldn't be surprised." Banner shoved his hands into his pockets, and sauntered down the corridor. Even though he was a fairly small man, he managed to fill the space, as though the phantasm of the monster within lumbered behind him, shoulders dragging against the ceiling. Of course Banner would know. His was the biggest mistake of them all.

"I have to ask," I casually began, although I felt as though I was straying into questions best left unasked. "Why did you... um..."

"What, go green?" He raised an eyebrow in mock offence, making me blush. "Oh, sometimes it's good to let off a little steam."

"A little?"

He chuckled, but there was a strained edge to his laughter. "I thought I'd already apologised for that."

"Hey, it was a shock!"

"That's what they all say."

"It would be more of a surprise if they didn't," I added dryly.

He sighed. "You and me, monsters both."

"Hmm. Poetic. Also a little insulting."

He shrugged. "The initial sting wears off after a while."

"Huh?" I stopped, swung round to face him. "You've gotten used to being called a monster?"

There was a pained look in his eye, like he wasn't sure how to explain, or sure that he wanted to try. "It's what I am. Why try and avoid it?"

Was that what I was then? A monster, born and bred for chaos? The thought that I might never be able to break out, do anything else, was terrifying. But then who was I kidding? In less than a week it was back to being a lab rat. I couldn't afford to start making drastic life decisions; it would only make my iron-set path the harder to swallow.

Banner must have seen some sort of tectonic shift in my face, a hardening of my jaw, because he swiftly changed the subject. "Fancy getting out of here for a bit?"

"How do you mean?" I jogged beside him curiously, but he didn't speak again, instead descending through the belly of Stark Tower the long way down the stairs. Even when we ended up in the lobby, I still wasn't quite sure as to his intentions.

Bruce looked up at the ceiling, airing his words to no one in particular. "JARVIS, the doors if you would be so kind."

"Of course, Doctor Banner." The AI sounded as respectful as it was possible for an emotionless and surprisingly snarky robot to sound, and a hair's width of a second later the glass doors fell open, swinging a little in the breeze now gusting its way inside. A few passers-by looked on in admiration, a few raising phones to capture a picture.

Banner glanced over his shoulder at me. His expression was one of near-childlike mischief, a face only Tony ever seemed to wear. "Coming?" he asked.

It took me a few seconds to process his question. "Sorry?"

He smiled gently. "I said, are you coming?"

I stared dumbly. "What, outside?"

He shrugged. "Where else."

The fresh air smelt so good, but I continued to baulk. "With you?"

"Yes."

"Outside?"

He smiled again.

"Not that I don't want to." The words poured out in a hurried jumble in case he might withdraw the offer. "But aren't I under house arrest?"

"Let's just say I don't quite agree with the rules Fury's set up. You shouldn't be kept cooped up in here for days on end like some sort of animal." His voice was slightly lowered, guarding his words from the ever-watchful presence of JARVIS.

"So, to paraphrase, you're taking me for a walk," I said dryly. "If it's any consolation, I won't foul the pavement."

He chuckled at that. Not for the first time I wondered he and the Hulk could coexist in the same skin when he seemed so kind. "Oh, I heard your humour could bite, I just didn't realise quite how hard." He gestured to the open doors. "After you."

I walked towards the exit, every nerve screaming at me to break into a run. I could leave the doctor in the dust and be out of eyesight before he even had a chance to raise the alarm.

The doors began to falter, closing slightly in the manner that one might cross their arms. JARVIS' voice echoed overhead. "This contradicts my protocols."

"Yes." Bruce smiled pleasantly, hands in his pockets.

"I'm not sure that-"

"Sure you are." His voice was sinisterly calm.

There was a nervous pause in which I imagined JARVIS trying to swallow past the dryness in his throat. Well, if he had a throat. "Director Fury-"

"JARVIS." The single word rang through the room with unmistakable authority.

There was another heavy pause. Then: "Of course, sir."

I raised an eyebrow at Banner as the doors opened again, with some measure of reluctance. He only smirked as we stepped out into the blinding sunshine. "You've got quite a way with him."

Banner strode ahead, shoulders hunched against the press of people. His smile was gone, head slightly ducked. He seemed painfully conscious of the sudden presence of people. "He has a constant fear that I might go green and rip out the finer parts of his mainframe. I certainly didn't do too much good to his systems last time. As a result, he has a habit of appealing to my good side." He issued a short bark of laughter. "Tony hates it."

I nodded vaguely, only half listening. The throb of the city had once more seized upon the rest of my senses: the heat, the smell - so many smells - the brightness of the sun on steel. Every fibre of my being screamed at me to run. To lightly bound into the anonymity of the crowd, and be lost forever. All it would take was a second, a sudden rush of speed, and noise since Bruce would no doubt shout out in alarm. Then I was free.

The temptation was huge; I wasn't sure how I was able to keep myself at a steady walk. The whole way I bounced impatiently on the balls of my feet, ready. Eyes skittering over the crowd, seeking out gaps and vulnerabilities, natural clearings in amongst the forest of people which I might use to my advantage. My whole body was rigid with anticipation. Now! Go now!

And yet I didn't. Every sidelong glance from Bruce kept me rooted in my spot at his heels like an obedient dog. Even then, it wasn't so much out of the fear of what he might do, what I knew he could do should the need take him, but out of something shockingly akin to... concern? I wasn't sure how to name the feeling, the sort of softening in my chest whenever a reassuring smile flickered across the doctor's face. He had taken a risk in trusting me, and the odd thing was that I felt obliged to show him that I could be relied upon, to prove his judgement right. If I were to run, he would suffer the consequences, him and the others. Steve. Tony. Even Clint, and however much I tried to forget her, Natasha too.

Why do you care? Every instinct scorned such concern that only seemed to serve as a weakness. Self-preservation threatened to overrule such concerns. From somewhere deep inside my mind floated the phrase every man for themselves.

"Everything okay?" Banner looked a little concerned. Something told me that he could see what I was contemplating, and yet he made no move to detain me, or hurry me back to the Tower. Instead, we continued down a side street, slowing our pace a little to a comfortable stroll, the sky rolling out between the rooftops in the manner of a bright blue carpet trodden lightly by a few wisps of cloud.

I forced a smile, and nodded. There was no way back. No matter how much I urged myself, I couldn't do it, not when I saw the amiable kindness in his eyes, the rare slump of his shoulders and hands casually pushed into pockets. An image of trust. Yet the day was still glorious, the air still fresh on my skin. In the realisation that escape would be mostly futile, I let myself relax, a small, genuine smile growing over my face.

Somewhere nearby, my sensitive ears could pick out a faint thrum of music, a hopeful tune that pushed vainly against the wind in a valiant attempt to be heard.