Action
Shiro hadn't returned to his normal self yet after that nightmare. Sure, he knew it had been a nightmare, but it had been so real and close to home. And he had attacked Keith, though not intentionally. So in complete conflict with himself, he neither wanted to be in the apartment or away from it.
So he was outside on the walkway of the apartment building for some "fresh" air when all of the sudden there was something that fell onto the walkway nearby, causing him to jump.