Well, if your Dad told you to help him with the case, and you went and hid, wouldn't you think it was safer to stay hidden if you were scared? His unaffected smile when Hotch opened the box was a little weird, but I suppose you could say that being in a room with the door shut in a shut box would muffle a lot of noise. Maybe. Probably. Possibly. When the Reaper was talking about how all Hotch had to do was take the deal, and Hotch was saying that he was just trying to get Haley to react, all I could think was that no, he was trying to get Hotch to react. He was trying to get Hotch to feel guilty and feel like this whole thing was his fault. Although it's probably both things, really.