He once opened the passenger side door in flight.
He would also pull the throttle back all the way and announce, "Engine failure! Whaddya do?" He also once sneaked a pencil eraser into the cigarette lighter and said, "Whoops! Electrical fire! Whaddya do?"
I could see him pulling something like this . . . but I think I would have called him on it a little sooner, and then radioed the tower to have the EMTs standing by on landing.
That would have been a VERY tense landing, though . . . especially in a crosswind!
Early on, we did some exercises using the doors to generate enough drag to steer the aircraft. Simulating loss of specific flight control surfaces. In the end, I think that my instructor had to employ those techniques to prevent the aircraft where he was a passenger from crashing into homes around Ensenada. The end assessment was a locked up control surface due to improper maintenance. Since he is no longer with us, his name was Ralph Buck. He was an instructor at Flying J Aviation at Brown Field south of San Diego. Over 50,000 hours of flight time and dead over improper maintenance of the aircraft where he was passenger.