In the Celtics’ world, where no feelings are spared and players always express their emotions, it wasn’t a big deal. But it could have been. At the end of the first half of last night’s Game 5 of the NBA Finals against the Lakers at the Garden, Rajon Rondo was handling the ball as the clock wound down. Paul Pierce, who had 15 points at the time, wanted the ball. Rondo planned to pass to Pierce, but the play broke down.