That Lu dude actually does have a pretty solid plan. He never wanted to be there in the first place, never wanted to participate, especially on Yang Kai's side, since he hates Yang Kai. By making Yang Kai look bad in front of his friends, he just made sure he will be kicked out. If he's kicked out, who can blame him for leaving? He couldn't just walk away on his own as it would be viewed as cowardice and deserting, but if Yang Kai tells him to leave, he naturally leaves.