I understand why he did that, but he should have come back onto Lebron. The initial gamble was smart, making Lebron feel like Lebron shooting a three was his best option, and that driving wasn't an option.
However, Pierce should have been more aware of the shot clock and got back sooner, and trusted his teammates to cover everything else.
Still, I won't use this as an excuse. The Celtics are in a very good position right now to potentially win this game. An 8 point advantage going into the 3rd quarter, where the Celtics get the ball first. If the Celtics have a decent quarter where they barely outscore, or even tie for points with the Heat, the Celtics have a greater than good chance of taking this game. Minor mistakes aside, along with the 3 pointers that have kept Miami in this game that I feel they should be more out of, the Celtics couldn't have asked for a better defensive start and offensive start against a Heat team you know is out for their head after what happened to them in Boston. So, with that in mind, the least we should do is be down about the fact that our lead is only 8.
We could be in much, much worse shape right now. I sure as hell won't complain about being up by 8 right now. The Celtics have to just make sure they come out in the 3rd and get the job done in that quarter, as it may very well decide this game.