It looked like he was on the rear brake before it all happened, and he may have gotten onto the painted stripes at the same time, it is too hard to tell for sure. But given the guys prior crossing of the paint, it is feasible. But I believe the bottom line is he used too much rear brakes, of which the R3 has plenty of.
bob
eta: after stepping through it, it looks like he was not on the paint with his rear, possibly his front though.