Orange rider was transitioning from left to the right, looks like he hit the motorcycle in front (misjudged closure rate and/or front rider had a problem/chopped throttle/panicked because someone was flying up his butt/who knows??).
20/20 after the fact, swerve left might be the correct answer, butttt, being on the right side of the track that had more 'open' space in front of me, to decide to swerve would have been a very hard to mentally process and execute in that time frame. By the time you saw/registered the orange rider going down, uttered 'WTH?", the flying bike is in your face.
Someone who practices swerving alot , lots of track experience, might have the reactive skill (both mentally and physically, emphasis on mentally) to have avoided, but you'd have to be razor sharp focused.......
What would I have done, honestly, hopefully I would have ducked, as low as possible and hope the flying bike didn't drop kick my butt. :-\