Most of the "civilian" world doesn't understand why police and others continue shooting at a threat. I finally figured out how to explain the rationale of continuing to shoot.
In a fist fight, you don't just quit punching because you landed a decent punch, you keep punching until the other fellow no longer wants to fight. It is the same in a gun fight. The primary difference is that in a gun fight, you continue shooting until the other person no longer wants to fight, or is no longer a threat. That may take only one round, and it may take many more.
I really like the way he sets his popper...it is a great training idea. There used to be some cardboard targets that would be supported by a balloon on a string, and the balloon would be placed in the head, center torso, or hip area. The idea was that you continued shooting until you popped the balloon and the target fell. I haven't seen those targets for 10 years though.. So the popper adjustment is really neat...