I am guessing we could have saved the taxpayers quite a bit of money by simply stating that:
You, the individual, have the ultimate responsibility for your own protection. We, the government, can only provide a reasonable effort in protecting society as a whole, and will never be able to protect individual members of society such as you.
The critical metric in any mass killing are defined as the difference in time between the killing begins, and the time when an armed citizen (or police officer) confronts the criminal with equal or greater force.
In summary - get off the social welfare wagon regarding security and protect your self. If you are present when a mass murder is taking place - run in the direction of the gunfire and shoot the SOB murdering other people - seconds save lives.