I'll jump in.
When you decide to use deadly force, you are accepting the fact that it may mean the death of the person on the other end. It is not realistic in this situation to fire one shot and assess whether or not the BG is out of the fight. In case it isn't obvious, while you are assessing if the threat is stopped by your magic bullet, the BG can get off a shot. That one shot can end your life. No, you don't stop shooting until the threat is clearly out of the fight. Usually, that will be when he hits the ground. THEN, you MIGHT be able to safely afford the time to assess. If the gun is still in his hand and he is still moving, then he's still a threat and worthy of being shot again, even when he or she is on the ground.
For a civilian, I have an even LOWER expectation of assessing whether or not the BG is out of the fight.
Our plan is to always stop the threat. You'll find that the vast majority of defensive handgun uses do not result in shots fired at all. The point is to stop the threat. If a BG is coming at you with a knife, you pull your gun and he abandons the encounter, you have stopped the threat and didn't even need to fire. If the BG in the original post had abandoned the encounter instead of pointing a pistol at the LEOs, they could have stopped the threat without shots fired.
This BG chose his fate by posing a threat to the LEOs. I have absolutely no problem with 110 rounds fired in this case.