Fair points anon, but there's nothing to say a shooter wouldn't tip authorities off to something a fair distance away to draw them away. I would expect we'd hear about something like that, but then again maybe not. It could be embarrassing or give away tactics other people could use. (stupid idea btw because they would get all kitted up and make sure they're mobile enough in anticipation of that).
If special forces were there it's still only one data point, could be a coincidence, unless it happened on multiple mass shooting instances. And we don't actually want that just to prove a point.
IMO, the best line of enquiry for events like this is did the perpetrator act alone, is there a case that an act like this was a false flag to bring about a certain change or cloud future issues, were any of the victims high value targets, was the location a center for previous investigations, are there any timing issues etc.
Going around saying it was a VR hoax or stage show is not going to get anyone anywhere without incontrovertible proof. The video evidence is interesting for sure, but without the high framerate untranscoded originals it's just not going to be settled here.
If anons want to keep digging in that direction though I'm not going to comment on it, it's their choice.