First Flash fic! Not my first fanfic, and definitely not my last Flash fic. 3

Run.

Run until your legs hurt, until you're gasping for air, until your heart is going to beat out of your chest, it hurts to breathe, it hurts to stop, then take a breath—

And keep going because that's not air, it's water, you're drowning.

The Streak tries to breathe with every ounce of being as the gas infests his lungs, sinks into his pores, consumes his being.

His gasps are not a coordinated response; they're a panic response, triggered by the immediacy of the need for breath and the simultaneous need to expel the water from his lungs. He can't breathe water, he needs air, right now, and it's that desperation that shoves him to his feet and makes him take off.

You can do extraordinary things under pressure. The Streak runs miles without drawing a breath, until the black spots are all he can see, until he's stumbling, crashing into walls, all but losing his grip on reality twice.

Then he crashes into the S.T.A.R Labs' main console and sets a whirlwind in motion.

Except no one seems aware of his flailing hands, his straining lungs, as they haul him to the table, and he can't see anymore, he's only aware of shapes and sensations, a throbbing head, a pounding heart, and he needed breathe two minutes ago, now he needs it like he needs a beating heart: he's going to collapse and die if he doesn't get it back now, nownownow.

"It's still – it's still inside me," he chokes.

Cisco babbles something and Caitlin snaps something else, and he's aware that this is going to hurt, a lot, but he wasn't ready, how could he be, for the needle she slams into his chest, drawing a syringe-full of gas from his lung and retracting it in six-thousand-milliseconds (and he hates the Streak and his ability to slow time down when it needs to speed things up), the sensation lasts forever, it's pain beyond understanding, and his lungs are going to explode.

The last thing he's aware of before unconsciousness sweeps over him is the oxygen mask Cisco fits over his face and the utter, extinguishing effect a single thin breath has on him.

. o .

"You really need to develop a safer strategy for sample collection," Caitlin tells him when he comes to, lethargic, slow, shaky with relief.

Barry doesn't respond right away, still sucking air from the oxygen tank.

"I mean, I appreciate the thoughtfulness, but Barry," she puts a hand on his knee and he lifts bloodshot eyes towards hers, "you can't ingest a toxic substance again for a sample specimen, regardless of how valuable that specimen is."

He nods slowly, trying to convince his body that it's okay, his head still spinning. Logically it was an easy decision to make: they had to learn more about the meta-human to bring him down, and collecting a sample – however risky – was the best way to do it. Still, emotionally, physically, he wasn't ready to drown. It was jarring. He's healing rapidly, recovering phenomenally from a life-threatening event, but the fear and adrenaline don't run through his system as quickly.

Amid the pandemonium of his own thoughts, listening to Caitlin lecture him mildly is almost soothing. Cisco and Dr. Wells are at the station discussing their findings, and Barry knows he'll want in on it, too, but right now – right now, he just wants to breathe.

Caitlin's rant takes a brief intermission when he sits up to cough, harsh, heavy. "You might be feeling asthmatic for a few hours, but the worst of it should pass soon," she says, taking a seat beside him, but he doesn't focus on that half as much as the way she rubs his back in slow, sweeping arcs, grateful for the grounding sensation.

"What the hell was that stuff?" he asks once he regains control, lowering the mask from his face.

"We're still analyzing it," Caitlin says, getting up to replace the bag on his IV line as he sinks back against the pillow. "It'll take at least half an hour before the results are in." Eyeing him skeptically, she adds, "Are you okay?"

"You shoved a giant needle in my chest," Barry reminds her lightly, almost teasingly, except, equally seriously, ow. He'd have a hell of a bruise if it wasn't already healing; as it stands, he remembers the stabbing sensation too well to forget it just yet. Pain is almost as mental as it is physical; a phantom sensation is almost as powerful as a real one, and Barry knows he isn't going to forget how much pain a very big needle can inflict easily.

Caitlin winces sympathetically. "I promise I wasn't trying to cause you more pain. And I want to keep working on an anesthetic that might work on your metabolism. It's a long shot, but it could come in handy," she explains. "Especially if we ever encounter a speedster we need to take down."

Barry nods agreeably, even as the thought of another speedster makes his blood run cold. His upper hand comes from his speed; without it – or, more accurately, on a playing field where it's irrelevant – well, he's just Barry Allen. He heals fast, but taking down an experienced fighter – even a decent fighter – on his level could easily do him in.

And if they're faster than you?

He pushes the thought aside. As far as they're concerned, he's the only speedster on their future receiving end of super-anesthetics, and until he has to, he's going to keep thinking of it that way. Central City may have evil meta-humans, but it also has "The Streak," and damned if he won't stop gaseous monsters from taking innocent lives and anyone else who tries to do the same.

"Do you think we ever will?" he can't help asking.

"What, find another speedster?" She looks at him, sizing him up, and shakes her head. "I don't know. But nothing's impossible."

"Nothing's impossible," Barry repeats idly, musing, before another series of coughs banishes speedsters from his mind, his hand reaching for the oxygen mask Caitlin passes him.

He really does need a new strategy for outwitting gaseous monster meta-humans.

But for now, he's got a team to pick up his slack, to reach for him when his best efforts won't cut it, and it's good enough for them.

It works.

For now.