The media is twisting the story for over-hype...as usual.
Not that I like or care about Tony Robbins...but walking over a bed of coals is done in various venus more often than you think. It's a pretty neat rush.
You see...the trick is to move at a quick steady pace. There's a layer of ash over the coals...insulates a bit against your skin. Foot should have brief contact with the ground. Walk quickly, steadily, having foot on the ground as briefly as possible.
Also you can see areas where the ash covers the coals denser than other areas. Darker gray spots. You want to place your foot there if possible...so you're selecting where you're walking.
Now there are going to be a small percentage of people that have sensitive delicate skin on the bottom of their feet. Ah well....it's gonna happen.
Now here's the part that most people miss. 21 people hurt...but the convention at 6,000 people. Now I'm sure not all 6,000 people did the walk, but I'll bet a pint of Guinness that over a 1,000 did it. They had what...8 lanes of coals..and it took 90 minutes to get the walkers through? 21 people out of that total? Not bad. Did the media interview the ~980 people that actually did it successfully?