How come after Batman interrogates Joker and has to choose between Harvey and Rachel, he tells Gordon that he will go after Rachel letting Gordon go to Dent.... however, afterward we find they actually switched destinations? Did they make a cell phone call en route and decide to swap places? It doesn't seem there's ever any explanation for that. I can understand why Bruce's first thought would be to save Rachel, but then he goes for Harvey because he decides he is the more important one for Gothem, but they never really say if this is the reason.