Glad to hear you're OK.
Here's what I think may have happened.
You weren't steady on the throttle - you can hear it wavering just a little a second or so before it lost traction. I'm thinking that if you would have kept steady throttle you may have survived without crashing. May have rolled off throttle, and the rear hooked up again sending you flying.
Agreed with what ZX600 had to say about body position. You're crossed up a bit - your butt is moving farther than your shoulders. I'm also wondering about your arms - they appear to be very straight most of the time. It becomes very apparent on the back straight at 6:07+. Your head height hardly changes at all from the straight into the turn at the end.
So, with better body position and throttle control, you would have been OK.
Watched it again, and yes, slightly crossed up. Agreed on the head position. I need to work on the left side. I feel much more comfortable on the right.
I think the FAST course 1 & 2 is on the calendar for next year for better body positioning.