One thing that nobody wants to discuss is it was possible that the minuscule police department thought this was more than a single gunman, possibly a group of armed individuals, there may have been a panicked phone call to the nearest group of people thus the Army that was very close to get there ASAP. I don’t think they had any SWAT capability.
I would rather see this happen than waiting an hour or two for SWAT to show up and they sit while dozens of people are being slaughtered.
So if there was a mass mall/school shooter on the loose and an Army or Marines base is just a few miles away we cannot use them because we fear posse comitatis? (sp?)
Simply supposition on your part to have circumstances fit the response........