It is my call for the moment to put this on hold.
We don't have enough info to discuss motivation. We can all propose tactics and what we would have done - and that all might be hot air in the horror show of a crowded dark venue with gas and an armored assailant.
We can all vent about the attacks on the RKBA that will occur or speculate on motives.
But we don't know.
We don't want multiple threads to spring up.
I've asked other staff for how we should handle this - so I'm closing it for our decision.
Till then turn your hearts and prayers for the victims.