So you lynch the cc who's guilty.... and it's scum. Now you have 100% proven cop and doc alive and too high a chance that cop will find second partner...
If he cc's, he's obvious mafia. What are the chances that mafia fakes guilties cop? Low. If cop guilties scum, partner needs to cc. Yes, it gives ONE "team", but to the rest of town, there's nothing at that point to prove whether or not that team is guilty.