A gunfight is not like a day at the range. A gunfight is fast. It is unexpected and, as you can see in this surveillance video, you will rarely have the benefit of a perfect shooting stance or even a two-handed grip. You have got to do your best to train for such bizarre situations.
Practice one-handed shooting. Practice shooting from behind cover. If you can, practice shooting from compromised positions. The good guy in this video didn’t do everything perfectly, but he did enough correctly to win the fight. And you know the old saying: “Ten years from now, no one will remember what caliber you used, what brand of ammo you used, what shooting stance or brand of holster you used. The only thing that will matter 10 years from now is who is alive.”
Train so that you will stay alive.
Did you notice that even after being shot several times, the robber was able to get up and run to the door? Pistol rounds are not powerful enough to guarantee a one-shot stop. Keep shooting until the threat no longer exists.