(
That brings up interesting questions: if Quentin had been the scientist who developed the potion to split himself into two personalities, would Quentin have been killed off, as Cyrus was - or would it have been a case that the show would have stressed that the Quentin side was good and not at all responsible for the evil his other personality had committed, so some way would have been written for the other personality to be permanently banished, but Quentin would live on?
Though that's a discussion for the Current Talk board...)