How safe is kungfu?

I'm relatively new, my exposure to kungfu that is.

I'm curious how the shaolin monks are not muscularly built, yet strong to be able to do some crazy stunts

and I was told they train all day every day, and temple life is exhausting...

How does their body have time to recover from the intense daily training?

How can they push so hard and not even have bruises on their body? And they are even vegetarians/vegans, no protein from animal sources?

In different forms of exercises, like powerlifting, you often see people doing stupid stuff, like bloopers, and end up getting hurt and breaking their bones or worst case, even dying.

I haven't heard or seen anything like this happen in kungfu videos I've watched. They seem invincible, but is that really the case?

From what I understand, everything has risks, but kungfu training doesn't appear to have, or at least that I've heard of.