At first glance I thought he was way to close to the kid and firing on the retreating suspect is almost excessive force.
HOWEVER, looking at the sizes of objects in the video and the angle, I think she was much farther away than originally thought. Second I think every shot, the BG and the clerk was done within :33 and :34. So in less than a second you have the BG shooting (not this is what we can SEE), he may have been shooting at the floor for all we know from this video. The clerk also stopped at 3 as soon as the BG was to the door as opposed to emptying a clip through the door at the guy.
Under those circumstances hitting 3 out of 3 shots is impressive. IMO, appropriate level of force, and thankfully everything turned out OK.
As for the woman with the kid, I am betting she was just in total shock. Which is why she was acting like she did.