Imagine an old HYDRA killswitch being found in the metal portion still attached to Bucky's shoulder, but it's nearly impossible to reach. Scott's pretty much the only one that can go in and disarm it via shrinking.
Bucky looks at Scott’s eager face for a long moment, then sighs deeply. He looks maybe just a touch too eager for the project for Bucky’s liking. Then again, he’s only just gotten off the Raft. When Bucky first escaped Hydra, even making the bed became thrilling, so maybe he shouldn’t judge.
“You want to go inside my arm,” he says, just to be sure. “As tiny-man.”
“Ant-Man,” Scott corrects. He’s bouncing a little on the balls of his feet - even if Bucky didn’t know where he’d come from, he’d’ve had him pegged in a second anyway. Men who can’t sit still get into trouble without something to do. “S’okay, not many people have heard of me yet.”
“Right,” Bucky drawls, “but what if you mess up and get big?” Scott bounces a little higher, shaking his head emphatically.
“Won’t happen. A) I don’t like it; it’s super uncomfortable, like, you have no idea, and B) it requires different equipment. Hard to mix them up.”
“He’s pretty good at it,” Sam says, speaking up from where he’s standing in the corner of the room by the door, keeping an eye on the empty corridor outside. “As much as it pains me to say. And it’s not like you have a lot of options.”
Bucky grimaces, feeling the plates try to shift - it’s a phantom feeling, like the movement should continue, the ripple of energy down to the tips of his fingers that are no longer there. “Urgh.”
Scott stills for a second, and makes an aborted gesture like he might have been about to reach up to grip Bucky’s other shoulder. “Look, I’m an engineer. I know what I’m looking for, and I know everything there is to know about the suit. You want this thing out, I’m your best bet.”
“This is going to feel so weird,” Bucky groans, but he reaches up to peel off the cloth cap at the end of his shoulder.
“Probably,” Scott says cheerfully, snapping on his helmet. It does make him look a little bit like a bug. “Trust me, Bucky.” His voice is a little muffled now. “It’s your life, for one thing. And also, I really, really don’t want to disappoint Captain America.”