When Babs runs downstairs in Mrs. Schumaker's house, the basement door opens out into the kitchen and the hinges are on the kitchen side. When Ronald shuts that door, the scene shows him pulling it shut from the kitchen side. When Babs knocks the hinge pins out to escape, the hinges are on the basement side.
When Ronald's mother is in the pantry waking him up, she has a tray at her feet. Ronald opens the door and hands the empty tray to her. At the end of the scene, the breakfast tray is gone, however, since the scene is shot in closeup's, she may have handed him the tray and he brought it into his room.
When Ronald is crawling out of the pantry, a boom mike is visible.
The secret room is a great idea but it is never really explained why Ronald must live in there when no one is in the house except his mother.
When police are questioning the mother for the first time about Ronald's whereabouts. The boom mic can be seen above her when she is sitting.