the conditions would have made taking him out difficult and costly in life as well. more importantly it is the ease with which people like this can load up on multiple guns and 3500 rounds of ammunition, plus kevlar body armor, that enable massacres. the more guns you have on people, the easier it is for people to fire them. the idea that arming other people will prevent or lessen these events is ludicrous, simply because the greater supply increases the chances of the events, making them possible and even easy, and the response with guns can occur only after people are already getting killed (in almost all cases) and will usually result in unintended deaths anyway. And even more importantly, this and other recent massacres occurred in places where it is legal to have concealed weapons and many people carry them around, yet they've not helped anyone yet. If it does happen at some point, it's certainly not going to make up for the increased frequency of gun deaths. 100,000 gun deaths a year??? Crazy is when you repeatedly do something that makes no sense whatsoever.
setting bombs happens but rarely works and you don't find a lot of suicide bombers in our country, fortunately.