He might hear a knocking sound nearby, maybe the hallway outside the room, but it sounds more like someone tapping on the side of a large cardboard box than someone knocking on wood.

"Okay, I'll bite. But this is giving me flashbacks to that one Christmas when Alice wanted the dollhouse and I spent the entire night before setting it up. This some kind of payback for not seeing her as often as I should?" a cocky male voice says, somewhat irritated but also amused, or at the least making a show of amusement to cover the irritation.