If you're the victim of a bombing, on the other hand, you probably won't have any warning or any time to do anything about it. By the time you figure out what's happened, you're already maimed/ dying/ dead, or one of your loved ones is, or whatever. Remote though the risk is, the randomness and immediacy of it are a lot scarier. I've been in close proximity to a car bomb; it's shocking because it's a lot bigger than you are, and whether you are a victim or not has absolutely nothing to do with your skills or reaction time, it's purely a matter of luck.
It's like getting killed by a falling tree or a sinkhole opening up under you or something. The risk of that actually happening is tiny, but what's scary is how helpless you would be if it did. Unlike car accidents or confrontations with wild animals or people, you probably won't get the opportunity to think/talk/fight your way out of danger in the former situation.If you think about movies, TV etc., people are always getting in jeopardy but worming their way out of it somehow or another. We find it much more shocking when we see someone get killed without having any time to react to the danger they're in.