have you all never thought that Nazgrim has his own brain, he does know when to quit, but he has a lot of hate for the alliance, MoP will see alot of strife between two sides, but nazgrim has witnessed what the sha can do first hand, both as a control of emotion or a physical manifestation. I think with what garrosh plans to do with the sha (control it) nazgrim will see the faults in garrosh, and i personally think he will be the sword that takes garrosh's head from its shoulders.