I can only speak to local oriented Law Enforcement in the U.S. but I don't think anyone is ready for something like this other than possibly Israel but their society tolerates a level of security that wouldn't work here. At least until we have something along these lines.

We are all about containment. For the most part we only carry sidearms and thin body armour. Our training is all about containing a situation to put the subject into a fixed place to allow the SWAT team to begin their operation. We don't really train for scenarios like this and it's assumed that our SWAT teams would be the ones having to run and gun with this kind of adversary. Obviously, if it does happen it will be the front line patrol officers having to do it. Active shooters are a major threat both from the operational and tactical perspective. Look at what happened with the former Ranger tabbed suspects that took on the FBI in that infamous shoot out in Miami.

I am fortunate to work for a Department that has an outstanding Firearms training unit that does look at current events and changes their training based upon them. We do train for multiple threats and active shooters trying to roll your flanks and such. But, it's still tough to be confident about dealing with something along these lines.

We are very risk adverse due to the amount of litigitation that is part of our day to day operations. This has changed to some extent due to our school or Mall shooter scenarios but it's an extreme command and control issue to deal with multiple entry teams running around in a fixed location. There is going to be extreme chaos and it's hard for me to imagine anyone could do much better under those circumstances. In this particular case the Police were directly targeted so their command and control was screwed from the get go.

On a positve level, I think we are better prepared than we were prior to the Hollywood shootout where the suspects were heavily armored and carried long guns. It spurred Departments across the nation to develop patrol rifle programs and improve active shooter training which are good things.