To paraphrase the pilot's dictum "any landing (gunfight) you can walk away from is a good one". BUT, I don't see this one as perfect though. My nitpicks are the following;- the robber had the cash drawer and was at/near/out the door, and with people shooting at him the moron RETURNS?
Take the money and RUN, fool! 
- when faced with an armed (especially armed with a shotgun) threat, you do not go "bang-pause-bang-pause-bang-pause".
You go bangbangbangbangbangbangRELOADbangbangbang..... until the perp is on the floor. THEN you pick up the phone and call 911. The ladies didn't do this, and that's why one of them ended up in a wrestling match for her gun that could very well have left one or both dead instead of just one getting stitches.....- it looked to me like the ladies were connecting; maybe they need to consider bigger caliber hardware....