Exactly. Our infrastructure is so vulnerable, that I can think of multiple ways to disrupt daily routine and kill multiple people even without a gun, let alone suicide bombing -- dismantle&#x2F;block the rails, drop an obstacle on a busy highway, poison the drinking water, cut electric wires open, sabotage industrial&#x2F;power plants, set buildings on fire etc. heck, even shouting out loud &quot;he&#x27;s got a gun, run!!&quot; in a crowded space could result in multiple injuries&#x2F;deaths. 
If there were so many determined terrorists on our soil as various governments and agencies want us to believe, they <i>would</i> cause a significant damage, not just stage occasional attacks that are statistically insignificant. The smallest dog barks the loudest.