So I joined up a game and got stuck with a citizen. Boooooo.
However, I figured I'd have a little fun with it. I wish I saved the replay...interesting game.
Anyway, I waited a couple of rounds and then announced that I was a doctor. That night I put on my bullet proof vest and it saved my life. The next round, the real doctor died by a serial killer. I was claiming to be a town random doctor so it was still believable. The Sheriff was revealed by this time and I kept claiming I would heal the Sheriff. For the rest of the game, the Mafia spent their time ignoring the "healed" Sheriff and was trying to kill off whoever was protecting me from being killed. After enough wasted nights (killing some townies and neutrals), the Sheriff had enough time to investigate who was left in the mafia and the town won, and only then did I reveal I was just a citizen and the Sheriff was open for killing since the first and only doctor died.
Interesting match, for sure!