There are some in the general population, and a few chasers have gotten whacked also. The chasers know better....sometimes they get too close - that's how a lot of them get it. You got to have a way out of the situation before you get in to one. You could get stuck on a muddy dirt road....but that doesn't stop a tornado.
Chasers chase for many reasons. First is for $$$...if they get a really good video, some media outlets will pay handsomely for it. Secondly.....some do it for scientific research.... others (possibly the majority) do it for the thrill aspect, which is kind of a downside. There are many ways to get a high....this is a very hazardous way to do it.