Again, 'pipe bomb' comes to mind. I suspect even if he wanted the thrill of a gun kill firing a pistol one-handed and chucking pipe bombs would have done it. Also locked doors primarily make burglars try the next door knob, same concept here would apply I think. Tighter security at theaters moves the next one to the community center, tighter gun control just makes him pick a legal version and maybe modify it or maybe brings explosives from home to supplement it.. I won't deny we might see a drop off in these if we ban assault rifles, I rather doubt it but maybe, I just can't imagine in this case the ban would have mattered, except maybe to make things worse. It sounds morbid but he didn't really kill that many people, one toss-able IED would probably have done more harm.