[It's because he knows how much this must mean to Bucky that he plays along. He forces himself to take the cup in his hands. Steve's eyes widen as he does so. The why is clear fairly quickly.] I can't feel it. Bucky, I can't feel it.
[Genuine fear settles into his eyes as he flashes back to those voices over his frozen body. He looks up at Bucky desperately for help.]