We don't know how many times he was hit or where, but 8 or 9 shots were fired. Since he was running it is unlikely that most hit. It is very difficult to hit anyone that is moving.
True, which is why I train for this constantly with Airsoft. I was way too slow at acquiring moving targets and couldn't hit crap a few months ago, but I rarely miss the COM at 7 yards or less now.
There is no perfect solution to a situation like this.
Also true, but I think that the officers in this video could have done a lot better than they did. For one thing, they should have been ready to fire at any moment, but were extremely slow in getting the first (probably inaccurate) shot off, even with several officers present.
The first cop who was attacked got way too close while casually toting his rifle in his weak hand, and elected to bring a nightstick to a knife fight, with predictable results. The rest seemed too afraid to do anything besides running away when the bad guy went after them, and they couldn't even do that effectively.
As for how this tragedy could have been avoided, for one thing a Taser would have come in handy for that first cop. His other hand should have been holding a pistol in that case, ready to fire immediately in case the Taser failed. Staying on the other side of the fence would have been a good idea, too, since he had to come closer than the others and would likely be the first target of an attack (which obviously he was). The other cops should all have been ready to fire because the bad guy was, after all, wielding a deadly weapon.
What this video shows us is how effective and deadly a knife can be when used by somebody who is vicious and quick, and obviously we should respect that and act accordingly, but guns can be even more effective if they are used in the same manner, which clearly wasn't the case here. I'm NOT saying that a person armed with a gun will always prevail over a person armed with a knife--reality just isn't like that, and people can be hard to stop sometimes--but guns do offer range, and should be used while trying to maintain some distance from the knife-wielding (or even barehanded) assailant. From the video, clearly turning tail, running, and tripping is not a good tactic for survival, but backing away and firing rapid, accurate shots (from "retention" if necessary) will at least give you a much better chance.
My impression from the video was that most of the officers were holding either rifles or batons before the melee began, and that he still managed to get two of them down before any shots were fired.
They just weren't prepared for such a basic scenario at all--not only in terms of training, but from appearances it's as though they truly could not believe that the guy would go berserk on them. From what I've seen, that's not common in the US, where cops pretty much expect people to go berserk--it's part of their training.