"We actually at one point had to shut the race down and stop it," Grylls says of his Amazon adventure series. "I think it was eight hours or so, which is pretty rare for us to have to do that. But people’s lives are on the line, we had people we did have to airlift out, with really serious life-threatening infections. That’s the thing about World’s Toughest Race, you’ve got to look after yourself all the time. You take your eye off the ball and you get a little cut, and you think it’s inconsequential, and before you know it, a day in, your leg’s ballooned up. People can die super easily like that."