As F-5 said, there's a difference in response depending on how much information you have and your existing knowledge. One of my biggest complaints about weather coverage on TV and society in general is the herd mentality. We are programmed to think that all instructions must come from a central authority and that authority is not to be questioned. For our own safety we must do as we are told. While this arrangement might work pretty well on average, it's not a good idea to follow the voice of the telescreen blindly.
Here's the deal. We all have sovereignty as individuals. We should all make our own decisions. If I had a debris ball headed straight for me with 15 minutes warning, I'd probably consider leaving town. But even for experienced storm watchers with access to high res radar data, there is uncertainty in the track and position of tornadoes. That, coupled with the fact that you are leaving all shelter behind when you get in a car, makes the decision more difficult. I lean heavily towards hunker-in-the-bunker rather than warp-nine-just-in-time.