It's like watching art happen, Parker realises, like watching Sophie charm a mark, or Nate plan a con, or Hardison tiptoe around a security system.
There's a grace and a precision to it that reminds her of the light touch she uses when picking a lock.
Sitting cross legged on a rafter, looking down into the gym, Parker watches Eliot train.
He's working on his own, practising one of those patterns, the ones where he's fighting an imaginary opponent. Each move is slow and controlled, fluid and graceful, the snap of his strikes the only indication that she isn't watching a dance.
His concentration is absolute and, as he turns, Parker sees that his eyes are closed.
He shifts seamlessly from following the pattern of movements into moving in his own way. Parker can pinpoint the moment when he breaks the routine, shifting from form-movement to function-movement, from moving in a style invented by someone else into moving wholly like himself.
Now his eyes are open, his strikes shorter and harder, his spins faster and his kicks low and mean. Parker has seen him fight like this many times, seen how much damage those fists and elbows can do. It's at the same time beautiful and terrible to watch.
Sweat darkens his bandana and his t-shirt as he works, his breath coming fast and short. Parker has rarely seen him out of breath but he is panting now, pushing himself to his limits.
He's been training like this for two hours now, first punching the bags and working with a sparring partner, now on his own. He switched off most of the lights when his partner left, and now he trains in near darkness.
Parker understands this drive for perfection. It's the reason she picks locks over and over, steals things only to return them, and plans heists in meticulous detail. She needs to know that she can do it, craves the satisfaction of knowing that she can do it perfectly.
Eliot has to know that his fighting technique is flawless. All their lives depend on it every time they start a job, especially the kind of jobs Nate's been finding for them lately. Eliot has to be able to fight anyone – giant henchmen, assassins, gangs of thugs… Anyone.
He's tiring now, Parker sees.
He's slowed down again, back to the stately dance of the kata. His long hair is matted with sweat and his chest heaves as he fights to control his breathing.
He's starting to limp where he's overstressed his ankle practising kick after kick, and his dodgy shoulder is clearly hurting him. He finishes the kata and stands alone, shaking with exertion in the centre of the mat.
He takes a breath and looks up, unwinding the strapping from his hands. He squints slightly and then sees her up in the roof.
"You want a ride home?" he isn't surprised to see her; she sneaks in to watch him train regularly and he's given up complaining about it.
"OK." He rolls his shoulder, frowning. "Gimme five for a shower." He slings a towel over his shoulder and heads for the locker room.
Parker drops lightly from her perch and wanders around the gym, not touching anything. She promised. If she takes anything from here, Eliot will be mad and he won't want her to come any more, and that would be sad.
Because watching Eliot train is one of Parker's favourite things.