I preferred the "Self Debrief" method when crew performance was just plain lacking.
I would take the video down to the training room....have the two "Students" grab their coffee....and when they got sat down and comfortable.....on came the video and I went out to get my own coffee,
Invariably.....left to watch their performance as spectators rather than participants....the actual debrief and subsequent training went a lot better as they were prepared to listen to suggestions for improvements.