Naturally, he doesn't look where he walks. He's too focused on what he's planning to be doing in a minute: fixing the air conditioning and making everyone on the bus feel better on their trip to the Shatterdome. So he doesn't see what's ahead of him in the next second.

"Oof!" And he staggers and clutches frantically at the seat ahead of him.

Blinking, Shirou straightens up, still clutching the edge of the seat, to stare at the man addressing him. "Yeah, but that means I could probably make it a little bit better. What's the problem with that?"