[It's not only Steve who looks terrified, then, if only for a second -- Bucky can't allow himself to show just how afraid he is. If Steve's freaking out, he has to keep it together. He has to.]
Hey, Stevie, it's okay. It's- you know how your hands and feet get cold real fast, faster than anythin' else in your body? That's gotta be it. Just, warm 'em up and you'll get the feeling back.
[He doesn't trust the cup, its warmth fading fast in the cold, and so he takes it away again, places it on the floor next to them, taking Steve's hands in his, flinching when he realizes just how freezing they feel.]