The riders behind him distracted him, they were riding pretty hard, and the jumble of tar strips in that corner did him in. The rider behind him put the force of his turn on the clean section of road past the tar strips.
Considering the sides of the road, and the oncoming traffic, looks like he picked about the best possible place to take a break.
Definitely a skilled rider, but skill can never make up for poor judgement - Good judgement can make up for a lower skill level. You won't be as fast through the curves, but you won't crash yourself out, either.