If working at a police department with a very highly-regarded active shooter drill program taught me one thing, it's that a typical citizen having a gun in an active shooter situation will almost never lead to "safer" or more positive outcomes.
I am so tired of hearing that "the more people that have guns in public places, the safer we are." I don't care who uncircles me for this - the misleading statements around this issue are just piling up and I hate watching this mentality be too "un-American" to challenge.
If you are not well-trained in close-quarters armed combat and response, the chance you will be able to effectively utilize a firearm to take down effective attackers in an active shooter hostage situation is exceptionally low. Especially when there is more than one shooter and they are armed with automatic weapons. Odds are you'll just make things worse and create a higher body count.
Now, should an off-duty cop potentially try to intervene in an active shooter situation? Sure - he or she could make a difference. They have the training. Non-uniformed military personnel? As long as they have the training. But the notion that arming your everyday person who heads to the shooting range once in a while is going to reliably "make a difference" in active shooter scenarios is an utter fantasy. Does the ready availability of sidearms stop mass-shootings from occurring in America? No, it does not - we still have more than any other western country.
I am not opposed to the 2nd amendment. I am opposed to blustering buffoons like Donald Trump who encourage untrained citizens to carry weapons in public as a "deterrent" to people who literally do not give a shit if they die killing innocent civilians with a gun or just blowing themselves up. This is ridiculous.