Stupidity: Dr. Tuskin says Regan's exorcism has made her psychological problems worse. Not only would Dr. Tuskin have to be grossly misinformed about Regan's condition prior to the exorcism to hold such an opinion, Regan's current "problems" appear to consist entirely of nightmares and absent parents, and she is otherwise shown to be a healthy, well-adjusted teenager.
Stupidity: I won't begrudge Father Lamont for instinctively grabbing for the first thing in reach to try to smother the box on fire (even if it is a pair of wooden crutches), but you'd think at some point he'd notice that he's just spreading the fire and making it much, much worse, but he keeps at it until the doctor finally returns with the extinguisher.
