Those are good points, but if someone is crazy enough to want to harm lots of people in a theater it's unlikely that the difficulty of surviving unscathed will

Those are good points, but if someone is crazy enough to want to harm lots of people in a theater it's unlikely that the difficulty of surviving unscathed will be a deterrent. And if the attack were not simply someone being insane (if for example it was terrorism intended to strike fear into people) then the success criterion is even lower b/c much fear would still be caused even if the only injuries were 5 people with smoke inhalation, and both "sides" in the issue benefit from amplifying the perceived severity. My point is that the specific munitions used does not significantly alter the strategic aspect of this (if there is any).