I think people have a very fuzzy grasp of what the human body is capible of. It is much safer to err on the don't try it if it looks dangerous side.
Taking these falls wrong would kill you instantly.
Yet, it's possible. I think it's philosophic.
On a practical note, they always do what's needed to land feet first. Something I (and many ma's) neglect to do on the comfort of a mat.
No, it's not about kicking someones ass or surviving the attack of the angry biker. (How many of you really think you train for that?) It's about reaching places within yourself. Embrace everything like this!