One of the key points to me is the lack of communication (among these departments). I don't understand why you don't have that. And why did the officers leave their point of cover? That completely violates standard police doctrine.

...when one considers that there are more than 750,000 police officers in the United States and that these officers have tens of millions of interactions with citizens each year, it is clear that police shootings are extremely rare events and that few officers--less than one-half of 1 percent each year--ever shoot anyone.

I've seen guys otherwise calm and collected lose it when they are chasing someone. We try to teach officers to recognize they are in a moment, take a deep breath and analyze it.

If there is an imminent threat to an officer, he doesn't have to wait to see a gun.

That is a pretty sad caper.

Most people don't have a clue to understand how much force is necessary to stop resistance. It's hard to put handcuffs on someone who doesn't want to be cuffed.