SOME cops are trigger happy, with their guns and their tazers....a recent event in Utah had a cop tazing a mentally disturbed man who was unarmed, and either off his meds or having a bad reaction to them. The man died. His family was there and between family and cop they should have been able to tackle him.
If they have time to shoot to wound, they should make the first shot from a designated shooter to wound any perp with a non firearm weapon. Give that a few seconds, if the perp is still up and threatening, shoot to kill.....
I read a story about a cop shooting an armed suspect point blank with a .357 magnum, 3 rounds, and the perp turned and ran down an alley. Cop couldn't believe that he had missed. Turns out the perp was on PCP, didn't know he was dead. They found him down the alley, dead, still clutching his weapon. He could have killed the cop, but this time turned out good.
OTOH, some cops are over confident that they can take out a perp withoug killing him, and it goes bad, and a cop gets killed.
Nothing is simple in these kinds of situations...