That being said...
For those who somehow insist that citizens carrying (OC or CC) in this situation could not have had any effect or deterrence, you obvioulsy believe that the murderer in this scenario didn't believe the rest of the patrons and employees to be unarmed? He not only believed it, he assumed it, and rightly so in our generally disarmed society. He shot no-one else, just those officers he knew were armed, and every evidence to show that he fled as soon as he received any true resistance.
Because the customers and employees, by circumstance or by choice, were unarmed, they were unable or unwilling to do their own civic duties by protecting their community, or themselves. And yes, every person in that store was in danger for their life, because, if a murderer is willing to shoot a police officer(s), whats one or two more Joe & Jane Schmos' for the list? I guarantee that if you ask each of them if they feared they were going to be next, they would most assuredly say yes!
This tragedy is a direct result of only one thing, complacency! Complacency on the part of the courts, the politicians, special intrist groups like the Brady Bunch and most of all, citizens that have been brain washed by all the above to believe that the only one responsible for the protection of themselves, their fellow human beings and their communities, are the police.
This is a dramatic punctuation to the fact that relying on the police to protect society is folly. Police are meant for two things, investigating crime and enforcing the laws, not for protecting society as a whole or stopping deadly crime in the act.
These police were failed by their fellow citizens, and the society that has placed too much expectation on their fellow human beings of whom they have appointed.
We have seen the direct detrimental effect of civilian disarmament in Europe and Australia. Criminals are at their most bold (and if this crime doesn't classify as bold, I don't know what does) when they have reasonable certainty that the public at large cannot or will not fight back. Civilian authorities can only respond so quickly.
This murder is pure evidence that America is quickly becoming viewed by the criminal mind as just such a population. When the criminals begin to disregard the public at large and begin specificly targeting our appointed public servants, the symbols of our laws if you will, than that says something about the disengagement of Americans as to their responsibilities toward themselves, and each-other.
My condolences to the families, the friends and the fellow officers of our fallen public servants, and my personal apology to each of them, on behalf of all the fallen officer's fellow citizens, who failed them.