I do not own Doctor Who in any way, shape, or form.

Summary: When Rose has trouble breathing, and develops asthma, it becomes apparent that running for her life is going to become a lot more difficult. And the Doctor's not sure he can risk putting her life in that much danger. No spoilers. Set series two. 10Rose.

It was night. The only light came from the two moons that shone high above, with a glistening of few twinkling stars scattered around the full circles. Not for the first time Rose Tyler found her feet pounding the dried dirt ground, as she once again was sent running for her life. This time across a dried up desert. Like always, her hair was falling about her face, her eyes set out in front, searching for her target – the finish line – the TARDIS. She could hear and see the Doctor's feet pounding just a few steps in front of her.

However, unlike the countless other times she had been sent running for her life, Rose was a lot more aware of the tight clinching pain in her chest. It squeezed at her lungs and made the battered breaths enter her mouth with much more force and with much more strength needed than what she was used to. The pain wasn't just the usual cry of 'Stop running, this is exhausting! ' but more of a pain squeezing up her lungs and telling her if she ran on for much longer it would soon become impossible for her to keep her legs going for much longer.

She slowed. She had to; her breaths were becoming erratic. Vaguely, she heard it. The thing they were running from. An alien species with a similar form to hedgehogs, only not as cute, and about thirty times their size. She had slowed to something of a fast jog now, and the Doctor had noticed. He was several meters in front and when he turned and when he saw how much her running speed had decreased he let out a yell for her to speed up.

She tried. She really did. He seemed angry that she had slowed. He wasn't used to it, and, quite frankly, neither was she. She wasn't used to this new terrible pain in her chest either, like her windpipe was closed in and her lungs were about to explode. She wasn't used to her breathing being this erratic and out of place, trying to suck in all the oxygen but only making the pain worse.

When she could only increase her speed a little she looked back to find the giant hedgehog alarmingly close. A hand cupped hers and she saw the Doctor pulling her along, his face heavy with fear, concern and slight confusion at her slowing pace. He pulled her along, making it impossible for her to even contemplate giving in to the stinging hurt in her chest. Her legs moved onwards, and her heartbeat continued to get faster, her chest got tighter and tighter, and the feeling that she was breathing through a very tight straw intensified.

As that feeling that she was about to collapse took hold – despite having the Doctor's firm grip in her hand – she finally saw a blue box a hundred yards in front of them. She almost cried out; never so relieved to see the TARDIS in her life! After she had managed to push herself those extra few steps, they met Time machine, and the Doctor pushed Rose inside, before throwing himself in and slamming the door behind him.

As soon as she was inside Rose didn't even get into the main part of the control room before falling to the ground and clutching her hand to her chest, breathing heavily and shallow. The Doctor turned from the door and looked to her, about to give her their large, and customary 'Yay, we didn't die!' hug. But his face switched quickly from happy relief to concern when he saw her sitting on the grating with her breathing quick, heavy and shallow.

"Rose?" He bent quickly down beside her touched her back, rubbing it up and down, staring at her fearful face, as she breathed heavy. "Rose, listen, slow down. Deep breathes. I know it's hard but you need to slow the breathing," he told her calmly. "Come on, big, deep breathes. In through the nose."

Rose looked at him, and her breathing stopped suddenly. She nodded and took a long inhale of air, and then let it slowly back out again. The Doctor nodded encouragingly as she did it again. "That's it," he whispered. She did it once more, breathing in deeply through the nose and letting it out steadily through her mouth. He nodded, "Keep doing that." The Doctor squeezed her hand tightly, before reluctantly getting up. "I'll be right back, just keep doing that, okay?"

He didn't wait for her to reply, and was up and running to a place she couldn't see. Rose continued the deep breaths, and to her relief it didn't take long for the Doctor to reappear. He had a stethoscope wrapped around his neck, the earpieces plugged firmly into his ears. She smiled weakly through her breathing. "Proper doctor… you," she managed to gasp out.

He hushed her to silence and returned the weak smile before scooping her up into his arms and taking her to the couch by the controls. He laid her down gently and urged her deep breathing on as he pulled up her top and pressed the diaphragm to her chest. She winced as the cold metal touched her skin, causing another sharp pain in her chest, to which her breathing let out roughly with a wheeze.

"Sorry," the Doctor whispered. He moved the diaphragm up and down her chest, slight frown tugging on his features as he told her when to breath in and out. Frown still in place, he took off the stethoscope and put Rose's top back down, scratching his head in apparent wonder.

"What is it?" Rose whispered. Her breathing was getting slightly better, she noticed, and the pain wasn't so bad.

The Doctor looked at her. "Any breathing difficulties before?" he asked. Rose thought for a moment, but then simply shrugged and shook her head. The Doctor sighed and absentmindedly stroked Rose's hair as he leaned closer to her, looking into her eyes. "You have asthma," he told her surely.

She stared at him, her breathing still a little heavy; sure she must have misheard. "I've got what?"

"Asthma," he repeated. "A chronic condition involving the respiratory system in which the airways occasionally constrict, become inflamed, and are lined with excessive amounts of mucus that –"

"Yeah," she interupted. "I know what it is. I just…" She stared at him, shaking her head. "I don't have asthma… I've never had trouble breathin' before."

"Well, you do now," the Doctor said gently. "There are lots of different triggars that can set off asthma. Running's one of them and –"

"But we're always runnin'!" Rose protested, interupting the Doctor and sitting slightly, causing a sudden pain to stab at her chest.

"Calm down Rose," the Doctor said, gentley pushing her back down.

"But, how can I have asthma… just get it all of a sudden? I never had it before…" Rose muttered, calmer but confused.

"You don't need to, it can affect anyone at any age," the Doctor replied. "Probably a reaction to something in the air on that planet brought it on, and the running just triggared it properly. Anyway, I think I've got something for it. Just carry on taking the deep breaths. Be back in a tick." Before Rose could protest he had disapeared again. She sighed deeply, breathing as steady as she could.

Again, it wasn't long before he reapeared. He had a small blue instrament in his hand, an L-shaped tube with a button at the top, which she recognised as an inhailer. She took it and pressed down the top button, breathing in the air that was released. "Better?" he asked, after she had done it twice. Rose nodded, looking away froom him.

She sat up. "I'm 'right now," she told him firmly. He let her get up, now her breathing was near normal. She sat on the sofa, gave a sigh, and looked up at the Doctor, shaking her head. "I'm sorry," she muttered.

The Doctor frowned at her, " Why?"

She shrugged, "Trouble I'm givin' you."

He smiled, "No trouble Rose. Why, looking after you? That's just part of the deal."

She nodded and stood up and rubbed her eye tierdly, "Right, well I think I'm gonna go to bed."

The Doctor nodded, "Okay." Then he sudenly remembered something, "Oh! Wait, take this." He handed her the inhailer. She stared at it for a moment, regarding it warily. "Go on," he urged. "Just in case."

She took it relutantly and headed off down the corridor without another word. The Doctor watched her go.

Of course it wasn't at all unusual for them to get into a bit of danger on their travels – anything but – yet he couldn't dismiss the idea that this time it had been because they had ran that Rose had gotten hurt. He hoped it had just been something in the air on that planet, perhaps something that maybe humans were allergic to, and Rose had merley triggared the asthma attack off properly by running… but if it was something else. If it had given her the illness for good… no matter how common it was, it was not a good thing when their lifestyle was considered. A main part of it involved running.

What if he was putting Rose in danger? What if she had another attack… and it was worse? What if he wasn't there next time? What if he lost her-?

No; he quickly shook that thought from his mind. Although looking on it, if she was in more danger than before with this life they were living, he might have to reconsider... everything.

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