I don’t have a background in firearms, but have seen our own police firearms teams in action, sadly, too many times. I think there is a fundamental difference between highly trained UK firearms teams and the police in the US, who as we know are routinely armed.
I suspect the average US officer merely learns to shoot straight, and is not proficient in the entry and containment tactics we see tactical firearms teams deploy in this country.
So, whilst there may appear to the layman to be some merit in suggesting that the police acted more swiftly to resolve this awful incident, the harsh reality is that, had they done so, they would likely have been lambs to the slaughter.
That is not what they are paid for, and it is unrealistic to expect it.