I love this kind of talking too...It's the playoffs, they just lost a game they thought they were going to sweep (Melo REALLY wanted to sweep them)so now they're amping themselves up.
Like Green said, it's their backs against the wall because they're expected to win, especially being up 3-1. Even if the C's force a Game 6, that would give them a scare.
Terry loves this type of stuff anyways, I remember in the 2011 Finals when the Heat were showboating in front of the Mavs bench, he had one of his best games after.