Without seeing direct pedal inputs (since this is all accelerometer based) and ignoring the other contributing variables like line selection, here's what I know:
The vehicle crested the elevation change and there was a lift of the throttle. Combine both of those and you have an extremely light rear end while under lateral load upon entry. Driver made correction too late/slow for it. The rear had begun rotating by 22.98 but the correction came roughly a second later, regrettably after the rear had inertia. This was not a chained event from T2 other than it placing him off line for a minimal input/load corner entry.
You mention "G's" multiple times in your original post and I think that's the important thing to address here: there is no absolute rule with G's, they are just one variable among many to analyze (1.6 does not equal spin, etc). The accelerometer (especially the one used in this video) is only telling one minor part of this story. It's the line and subsequent steering input, throttle input, and elevation change working in conjunction with/for the friction circle that caused this.
Here's some great material on the subjects if you want to dive deeper: