Philly has been dominant after timeouts! In the first half Boston had a 7-0 and Philly regrouped after a TO and took back over the game.
Here Boston was dominating, Philly calls a TO then comes out on an 8-0 run to wipe out the Celtic's brief run.
Rondo cannot make a play like that. It's one thing to have a lazy turnover but to just sulk and not get back was pitiful. KG had stopped the shot and Rondo would have easily gotten the ball back there.