Mishaps like these are always a sequence, or chain, of events. Some single component failed that in turn began the sequence of subsequent failures that lead to the to the ultimate separation of the entire rear axle from the car. Would be interesting to know just which component it was that started the whole thing off.
I've only seen one failure even remotely similar to this one and that was on a friend of mine's '70 Chevelle. It had a factory stock 10-bolt rear mounted to the factory 4-trailing link with coil spring rear suspension. During a burnout, the left axle tube (not the axle, but the torque tube that connects the center-chunk to the wheel hub) twisted and rotated inside of the center-chunk. As the tube rotated, it ripped the left side lower trailing arm from its forward mount on the floor pan. With the lower link separated from it's mount, all the load was on the left upper link and it couldn't handle it by itself and it failed too. With the left side of the axle unrestrained, the tire forced itself forward flattening the forward part of the wheel opening flush with the inner wheelhouse. Of course, this all happened with in a matter of a couple of seconds and feeling the violence of the failure my friend quickly got off the gas and on the brakes. With the brakes fully applied the axle swung backwards, with the tire damaging the rear of the wheel opening. When the car finally came to a stop, the axle was probably displaced aft about 30 degrees from where it's normal position should have been. It was a wild couple of second ride and it did extensive damage. Why the tube rotated within the center-chunk I do not know. I think maybe those tubes are just press fitted in from the factory. Somehow the torque of acceleration overcame the strength of that tube/center-chunk joint and it put the whole mishap sequence in motion ... literally!
