It looked like he grabbed a handful of throttle right after the wiggle started, but that may have been the perspective of the camera bike slowing down. The C-14 seemed to jet away as it crossed from the right shoulder to the left.Seen it before. In my opinion he leaned way to much off the seat, at the same time he went over some loose gravel and it caused the back end to kick about a bit. In his blind panic he probably did the worse thing possible and closed the throttle when he should have opened it a bit more to try and stabilise the bike. In closing the throttle it caused the bike to start fishing tailing really bad and then eventually come off. Very lucky he wasn't killed right out.