this kind of fall often results in broken wrists and collar bones, or at least a dislocation. Just skin? lucky!

It's crazy to see how fast they are going when it switches from slow motion to normal speed.

0:04 Guy in orange, 2nd place had his back wheel skip off a reflector. Such a tiny thing makes big.

Looks like the orange rider grounds his inside pedal. Very dangerous. Avoidable, but once you ground it, a wipe-out is imminent, as it lifts the entire bike off the ground. Often breaks the pedal or the crank, to boot.

I never broke a crank or pedal, but I did fold a number of rear wheels into tacos doing exactly this back in my riding days. I eventually learned to stop pedaling until I was done leaning hard in a turn, and to keep my inside pedal 'up'. I have also, at slower speeds, recovered from pedal grinding, but at these speeds he was hosed.

I think it looks more likely that his back tire skipped off the reflector than him grinding the pedal into the ground. Perhaps both?

why is the cause of the crash being debated, not only is it plain as day that it was the back wheel hitting the reflector that caused it, but it says that right in the description;)

It really looks like the rider in black with the dayglo yellow-green helm snapped at least his left forearm on his landing.