Do you wonder why Lebron just slacked off in the 3rd and 4th quarter in the finals?

In the Mavs game.. He seem like he didn't care. He didn't choke he was just sloppy for no reason. When the 4th quarter ended and the Mavs won he just hurried up and went to the locker room. Wade was just looking real mad with chalmers walking off the court and chris bosh was walking to the locker room crying and almost fell out (haha). I'm not trying to create an arguement but I'm just wondering why Lebron didn't try. In the Bulls game.. What was it game 5 or 6 when the Bulls lost to the Heat and the Heat advanced to the Finals.. The Bulls had a great advantage and could have made another game to try to go to the finals. But other than that Lebron and Wade just came out doing 3's, doing layups, getting fouls, or getting the layup and the foul. And they ended up winning, at first the Bulls were up like 12 points then Heat just started coming up and ended up winning. Why couldn't they do that in the Finals?