So they are trained, but in this case there wasn't necessary to shot a man (in the back). He could shoot on the leg, and conclude the story with a simple arrest but all we know that the us police are thinking "I'm a hero".
How about he could have just ran behind him for 2 minutes and kicked him to the ground? Like in those 70's movies? Or is that not done these days?
The arrestant was 50 years old, the cop was in his 30's. Not much of a competition...