The way Steve jumped back with a shout put Bucky on immediate alert, hand going to the knife at his back sheath before he stopped himself. The look of panic, fear, and confusion on his best friend's face gave him pause.
Then Steve was off and skittering away. Bucky blinked. There had been a flash of... something. Recognition? It was like Steve had been seeing something else, something that clearly had scared him.
Bucky took off after him, the crowd parting before him at the expression on his face. He ignored them all, focused on Steve's retreating back. "Steve!" he called. "Wait!"