At first they don't know what the device does, but after a minute or so Tony croaks, "Okay, I think I know now," and Steve looks over to see his expression set in the kind of calm that means he's freaking out pretty badly.
Steve feels his face tighten into the same expression as Tony unbuttons his shirt with unsteady fingers to show them his arc reactor, dark for the first time Steve has seen it.
"How much time do we have," Steve asks, and Tony shrugs woodenly.
"ETD four minutes," Tony says, and then staggers sideways to be caught by Natasha. "Make that three," Tony says, pale now.
ETD- Estimated Time of Death. "That's not funny," Steve says, and Tony shrugs again. Steve breathes in hard through his nose before jerking his head for Thor to move away from the HYDRA agent.
"We're trapped in here," Steve tells the agent, who glares. "We're going to be trapped in here for at least three hours until my people get us out. Which gives us an awful lot of time to punish you if Tony dies before that hatch opens."
He bends down so he's eye-level with the agent tied to a chair. "Give us the code to turn the device off."
The agent's eyes flicker towards Tony, the dark reactor, and then back to Steve's face. He's sweating badly, but he doesn't reply.
Steve grits his teeth. "Everyone in here is capable of inflicting intense amounts of pain on you. If you don't comply-"
"Hail Hydra," the agent interrupts, and Steve locks his jaw. They don't have time, and Tony's breathing is getting ragged behind him.
He feels all eyes on him as he takes ahold of the man's finger. "Give me the code, or I will break your finger."
Silence, and the man's eyes flicker with doubt and then alarm and pain when Steve breaks the first finger without looking away from his face. The man makes a muffled noise, biting down hard on his tongue so it bleeds, his face creased with pain.
"Tell me," Steve says, and the man breathes harder but doesn't say anything. Steve takes a breath and then breaks another finger, and this time the man cries out.
"Cap," Bruce says, and Steve doesn't look at him, doesn't look at Tony, doesn't look at anything but the man's face.
"Tell me," Steve says again, and the man stays silent. Steve breaks three fingers at once; a bone in his pinkie juts out of the skin.
The man screams. Steve squeezes the hand with all broken fingers, and the man writhes, screams louder.
"Tell me the code," Steve demands, jaw locked. "Nat, how is he?"
"Responding." A pause. "Barely."
Steve glances over his shoulder to see Tony sagging into Natasha, eyes hardly open. Panic shoots through him, and he turns back to the agent with steady eyes. "A lot of people don't know this, but after the Hulk, I have the most anger issues than anybody else on the team. I will let them out on you, extensively, if you don't tell me the code."
Chest heaving, the man shakes his head.
Steve gets a sick satisfaction this time when he dislocates the man's shoulder, and then breaks his elbow. When that doesn't work, he shatters his collarbone. Then he cracks his ribs. All in short, brutal movements, and he can practically hear his teammates' uncertainty from here. This, he knows, is not what they expected. To be honest, Steve is even surprising himself as he keeps talking.
"The Black Widow is in this room," Steve tells the man, who is whimpering now. "She knows how to make you feel more than I could ever inflict. If you let Tony die, I will set her loose on you. Is that understood?"
A whimper in response, and Clint clears his throat. "Tony's unconscious, Cap."
"Still beating, but it won't be for long-"
Steve takes the man's knee and squeezes until it shatters. "Tell. Me. The. CODE," he grits out, and squeezes until the man is crying, sharp sobs in the shocked silence.
Steve punches him in the face and breaks the man's teeth, careful not to break his jaw so he can still talk freely. He breaks his forearm. He breaks his leg in eight places, shoves the chair against the wall so all the man's wounds light up with pain at the sudden motion. He breaks his wrists, breaks all the fingers on his other hand and then squeezes them both.
All through this, the man screams, and no-one stops Steve.
"If his heart stops, so does yours," he hears himself say, hardly recognizing his own voice, uncaring of the man's cries, not caring about anything other than he isn't saying the code that will save Tony.
Natasha comes into view, bends so her lips touch the man's ear. It's at a hurried whisper, so Steve supposes the others can't hear.
"If Tony dies, I will paralyze you. But I will do it so you will be able to feel pain, you just won't be able to move ever again. You won't be able to do anything as we fill you to the brim with pain. I will get Steve to hold off on killing you, just so we can put you through as much agony as the human body can take. And believe me, it's a lot more than you think it is. "
She digs her fingers into the man's shattered knee, hisses, "Give us the code, now," and the man sobs until he's sobbing out pleas around a bloody mouth, and then numbers that Clint fumbles into the device.
Steve all but falls to his knees beside Tony, fingers of one hand pressing against the pulse point in his neck and pressing his other hand to the dark reactor. His knuckles of that hand are bleeding, probably from punching the agent's teeth in. Steve barely feels it.
"Got it, I got it," Clint blurts, and the device beeps, and Steve waits for two stricken seconds before the arc reactor flickers on and stays on, emitting the blue light that lulls Steve to sleep most nights.
He says Tony's name, but Tony's eyes stay closed. Steve assures himself he has a pulse, faint but there, and he's halfway through saying Tony's name again when Tony gasps himself away, shuddering upwards, hands coming up to shove Steve away, high noises ripping from his throat.
"It's me, it's okay," Steve says, holding Tony steady until recognition seeps through the panic and the noises die down to ragged breathing. He strokes a hand through Tony's hair. "You're okay, I gotcha."
He starts to take his hand off Tony's reactor, but Tony grabs his hand and holds it there, like he does sometimes after having a nightmare. Light shines comfortingly through their joined fingers.
"Shit," Tony rasps, and winces through sitting up. "What-"
He catches sight of the sobbing, whimpering HYDRA agent that Bruce is now tending the wounds of, and balks. His mouth opens and closes as he stares for several seconds. "Huh."
"I got carried away," Steve admits, and Tony looks at him. "Sorry."
"Don't be," Tony says, and grips Steve's arms as he stands, Steve standing with him. "I just- didn't you say a few months back that you thought torture was ugly, dishonorable and unreliable?"
Tony raises his eyebrows at him, and Steve shrugs. "Sometimes ugly, dishonorable and unreliable are the only options left. I couldn't-"
He swallows, flexing the hand that is sandwiched between the reactor and Tony's hand. "I couldn't," he says again, and Tony squeezes his hand.
Steve pushes his face into Tony's hair, closes his eyes and lets the thrum of the arc reactor, pulse-like, calm the adrenaline as much as it can. "I care about you more than I hate torture," he mumbles into Tony's hair, and Tony stills before he turns his head to press a kiss to Steve's neck.
"I can't tell if that's sweet or morbid," Tony admits, and Steve huffs a laugh into his hair.