I am curious whether those that are responding are veterans themselves, or a are familiar with carrying weapons.
There are a lot of factors that go into determining the appropriate defensive posture, including arming watch standers while in CONUS. Leadership must make a decision whether the threat is outweighed by the risk of negligent discharge, blue on blue engagement, or the bad guy overwhelming the watchstander, taking the gun and using it. The truth is (particularly in entry level schools like Naval Aviation Schools Command) , the person on watch may not have appropriate training in the use of firearms to be more help in a firefight than an additional risk factor. Sure, its a deterrence .,.and most mass shooters aren't any better trained --but these are considerations that the senior leadership must decide.
This is an age old question -- it is my recollection that Marine sentries in Beirut when a truck bomb exploded near a barracks were armed, but weapons were either unloaded or not "cocked and locked" the sentries were unable to engage the bomber. I think we had a similar issue with one of the ships that got bombed in the Persian Gulf ( that did lead to significant changes in ships protection posture in overseas ports).
Personally, I would be in favor of arming a watchstander if they have adequate training to be effective. Of course, that adds another training and qualification requirement at the command level. While that may be feasible at the operational level (ships and squadrons), it really is unrealistic in something like a Schools command. However, I also think that a better solution (in both military and civilian applications) would be to have persons who are trained and trusted to respond carrying concealed whenever there is a large gathering of people that are an inviting target for bad guys of any flavor.