Yamato is just starting to angrily jab his chin at Barry and then at Cisco's, complete with a mouthed 'your world, you go first' when Cisco looks over at him, and he goes very still.

(Maybe Cisco's like a dinosaur.

Maybe Cisco just won't see them if they don't move.)

"What? Us? We're not doing anything, are we, Barry? We're just enjoying this refreshing coffee. What are you doing?"