Yes, the Celtics threw this game away, but sometimes you know what just happens, and there's nothing you can do about it.
If the Celtics are the better of the two teams, they will win the series. If they lose the series, then they weren't the better team, and there's no shame in that.
The Celtics will come into game 5 and take care of business. It's the first team to win 2 games. If we can't do that, then we aren't the better team, and don't deserve to advance. Yes, a 3-1 would have been nice, but we can't have all that we want.