Why reveal Dr Gordon at the support meeting?
That seemed so stupid, why would you not keep him hidden until the very end where he's revealed to be working for Jigsaw? All the sequels and years of fans coming up with theories of what happened to Gordon, and they just randomly toss him into this scene in the first half of the movie.
That always just seemed so dumb to me, and the way he was acting in that scene pretty much confirmed he was working for Jigsaw and spoiled the ending.