I've thought about this quite a bit. And I think I've come up with a solution that could really limit the amount of deaths by these cowards.
the first 2-3 bullets in the gun should be non lethal bullets. They will be strong enough to stop someone for sure, but they are non lethal. So these trigger happy cowards when they get all hopped up on adrenaline and fear and can't control themselves will have a few shots to subdue the criminal before actually out right killing them.
and if it is a real safety concern for the cop, that 3rd or 4th bullet and the rest of the clip will stop them anyway.