Izuku seems to jump about a foot in the air with how surprised he is, dropping the file and clapping his scarred right hand to his mouth. His other arm is at a weird angle in a move more suited to interpretive dance than self-defense, but he needs to wag it about to express just how much he did not expect a locker to start speaking at him.

With a glance at the door to make sure no one is lurking beyond the frosted glass, he tentatively asks, "Uh... do you need help getting out of there?"