Mafia needs to figure out who's who, fast. Everyone in the mafia holds an equally important role, while the most important role in the town is the watcher. The cop is merely a backup to the watcher, and will likely be hooked (or even acted as) if he ever claims. Virgin sacrifice will be necessary if doc dies, but what if that doctor was really an actress? What if the virgin is an actress, trying to get a cheap kill on the watcher? Town needs to figure stuff out just as fast as the mafia. Anything could happen in this deception- and sabotage-based setup.