I think we all have a bad teacher somewhere in us. By which I mean we all have a self-serving shadow-side that we're not always in good relationship with. It loves praise, it does not like being contradicted, it wants to have its way with some of the women who come along. It's a rat's nest of trouble.
What do you do with what you have seen? Many people reject the teacher outright once they have seen his/her faults. That is because they feel betrayed. They were expecting perfection. Don't get me wrong, you may need to just walk away. They may be seriously bad news. But teachers usually also have some genuine gift that also needs appreciating: they'd maybe rushed in to teaching early, before they were ready. Or maybe that was always going to happen.
Just as Gollum had his part to play, so too do the bad teachers, for they expose the ways in which we are not sure of ourselves. Breaking away from them can be a drawn-out crisis. There is a voice in us we need to listen to, but we are uncertain of it. Things do not seem right when we do not listen to it. But the price of listening to it can mean leaving the metaphysical and social security of the teacher and group we are around. And there are good things about the group, so we try to put the doubts aside. But they keep coming back. It is a warrior thing. It requires daring, courage, self-confidence and ruthless honesty. There is a new centre waiting to emerge, around which your whole being will re-arrange itself.