I've seen a similar situation on video - the bike started tankslapping in the middle of the turn and after trying to control the slapping, which the he should not have done, according to the instructor showing the video, the rider chose to dismount.
As the bike was a Harley too and the rider was dressed the same, I will draw the very scientific conclusion, that this way of riding is a particular Harley rider way.
I should talk having tried the same thing my self, but I chose to stay on the bike waiting to dismount until the speed was agreeable for dismounting. On the other hand if there is a fall at the left side of the road, this, as Drewboid states: could have been his first good decision of hte day
greetings from a warm and sunny north
