To me, it's fine to celebrate a season-saving shot, but you have to remember, it saved the Celtics from almost certain playoff exit, but did not guarantee them advancement to the next round. They still have to win 2 of 3 against this team. So I don't think excessive taunting is necessary, or even a good idea. Better to "act like you've been there" and walk off in my opinion. That way the loss is crushing, not potentially motivating.
That Orlando team will come out strong in Game 5. We need to get Ray going early and get a big lead. Orlando can come back from a loss, even a bad one (see Game 3); what they haven't shown they can do in any series is come back from a big deficit in a game. To me, getting a 15-point lead early on is a good way to get the Magic to shift their attention to Game 6.