>YOU NEED A TEACHER!
This was the best dialogue they could interject into the climax's lightsaber duel? No introspection into how he just killed his fucking father?
The more you analyze this movie the worse it gets, we need somebody to rip it a new asshole a la Plinkett, I can already tell the Mary Sue situation will be worse as the trilogy progresses
By saying he could be her teacher he is posturing as an experienced leadership figure capable of taking on students. When he killed Han he did so believing he had no use for a father, that he is not a child and that he is doing his own thing. By saying Rey needs him as a teacher he is asserting a belief that he has become a father figure himself. He is attempting to become worthy of being the man who is justified in killing his father.
He was conflicted about killing his father that's why he lost the fight. Nothing says "I can't believe I just killed my father, what have I done?!" like excitedly trying to convert someone into your dark side disciple in the middle of a lightsaber duel.