IF someone is running by foot, he is not a threat to anyone, unless he is swinging a weapon of somekind. Shooting someone while fleeing is terrible in so many levels.
If he is running by foot at the officer, he is a threat. If he is running at another person, he is a threat. If he is running away, he is NOT a threat. Simply, "unarmed and running" is not enough information.
I get the feeling from talking to folks who were tribal police or reserves, that charging a police office will get you shot. Trying to take a weapon from a police officer will get you shot.
The answer is no sane officer is going to shoot a non-dangerous person. Although the nature of non-dangerous is the problem. Several cases (New Mexico) that should have been national outrages have gone unreported, but a case (Ferguson) that the final report said was justified were demonized (although the report does make some very valid points about the police department in general and should have been part of an investigation years before). How we keep ignoring the problems with flash bangs, I will never know.