Isn't Bear Grylls a little too lucky?

I think you are definitely right. But, obviously he scopes out the area that he films in before he goes there. There is no way he would ever actually put his life on the line. If he were about to die, they would quit filming, and help him, until he could finish the episode, and they would cut it all together to make it look convincing, or just not air the episode at all.