Mafia not killing to try and throw suspicion on town isn't unheard of. And yes, you're right that you're not confirmed, just claimed. But honestly, I don't see why a town who wasn't a doctor would claim to be one, it just makes you a target. The only good reason you would lie about being a doctor is if you're mafia.

If you are a doctor, then you're probably mafia, because I don't see any good reason why mafia wouldn't have targeted you by now. If you're lying about being a doctor, you're probably mafia. Either way, you're probably mafia. My vote stands.