There were other officers on the scene

One of which had a shotgun, the rest were armed with either their service pistols or non-lethal, the officer with the AR-15 took point because he had the most effective weapon for the sorts of long ranges you would see in a large department store with a reported active shooter

The other officers had warned the officer who fired to slow down and de-escalate, but they were ignored

It was not about deescalating, this was a (in two separate 911 calls from people in the store) reported active shooter in a now unknown location, and the officers were attempting to follow their training by forming into a group and slowly moving through the store to find and eliminate the threat, they were telling him to slow down because he was pushing ahead out of formation (I believe upon seeing the woman that was attacked, blood streaming down from the multiple lacerations on her head and face, attempting to crawl towards them for help)

The other officers had non-lethal options, but the officer escalated and fired live rounds in a situation where they couldn’t know if they were putting bystanders in danger

Lethal force is certainly authorized in (what is believed to be) an active shooter situation, with hindsight we can say he didn't have a gun but the officers at the time not only didn't know that, they were told the opposite, he was both armed and had already fired the weapon. Upon spotting the suspect, he was holding something (a painting) in front of him, concealing half of his body, and with a gun trained on him made a rapid movement with his free hand behind the painting, which is ultimately what got him shot

not militant thugs who spray rounds at the spray rounds at the slightest provocation with no regard for bystanders

The officer fired three rounds, one of which either missed or over penetrated, ricocheted off of the ground, and then penetrated a wall to unfortunately kill an innocent bystander hiding in a changing room behind

Cops are overwhelmingly shit and need better training, but aside from the almost freak accident killing of the innocent bystander, this was more or less a textbook handling of an active shooter situation by police who probably have never otherwise responded to one in their life, without the two errant 911 callers who apparently mistook breaking glass for gunshots the response would have likely been very different

I mean, there was an active shooter.

That was just shooting at all the things (like the floor), not even aiming. I wonder how many shots it took the active shooter to realise he was the only active shooter. Or was that completely besides the point of wanting desperately to use that gun?