It sounds like he buttoned off the gas because of the wheel spin so the weight shifted towards the front of the car. He had some opposite locking on, it snapped back the other way and the car steered itself into a roll. Are the rumors of oil on the track true? It looked a hand full off the line either way.
How come it was a flag start?
Edit: After taking a few more looks at it. The video is a bit hazy where it starts to go wrong because the camera moves just as it begins to slide. Rather than weight transfer from decel, it looks more like the car hops either from loss of traction and the suspension doing funky things or the track isn't perfectly flat?
Anymore angles to look at it?