Perhaps!
Besides, I have heard countless people on here, in self defense videos, elsewhere say they aren't sticking around to see what happens next in some scenario's. I know I have written on this forum a few times myself. I have kids and a wife. My throw caution to the wind and fight it out with a possible nutjob or killer to see who is the last man standing attitude died in high school. If I can get the hell out of dodge instead of standing there trading bullets, I'm a wisp of smoke. If tossing a few bullets behind me helps to that end, I'm throwing them.
There are other, some would say better, ways to get the hell out of dodge without risking shooting innocent bystanders. Unless you are in a field, there is bound to be some concealment and usually some cover. There are techniques to tactically retreat from cover to cover while placing relatively accurate shots that, at worst, serve as suppressing fire. Does this dvd set include any drills on firing while backing up at a much less than full run? The HUGE hole in your drill is that the efficiency of the technique decreases once the threat moves laterally. If you are reaching around with your right arm, most rounds will be landing to the threat's right as he is facing you. A person's arm does not reach very far past center when reaching around to the side at a full run. That means the threat to the threat is almost eliminated if he moves to the left. Picture a street. You're now running down the middle of the street. The threat just runs after you on the left sidewalk while most or all of the rounds are hitting on the right side of the street.
Granted, I'm assessing this technique using only the limited information available. Therefore, some assumptions about the drill must be made. So please correct what I may have gotten wrong. My gut feeling is, as stated before, this is a horrible drill that would have limited to no practical use in an urban environment and one's time would be much more efficiently spent on more practical drills. But I am willing to allow myself to be convinced otherwise.