"If things are good, and Barry keeps his children's snack here, then why aren't you living together?" he asks, not wanting to make Derek further elucidate on the different between hunting and what he just said when he still doesn't understand why the costume is only in play part of the time.

He's afraid Derek will kick him out.

"Barry would also be able to save money. And it doesn't matter where he lives because he can run to work."