I'm sure there are many other ways to blow up a 727, but roller clutch failure and overspeed of the front drum is what was explained above. The usual scenario is a driveline failure of some sort that damages the roller clutch. The drum explosion does not usually occur at this time but instead the next time the car is launched. The roller may hold even when damaged but then suddently fail under load. Since this load is most likely a low gear launch, your foot is on the floor when the roller fails sending your engine screaming onto the rev limiter. Remember that there is a ratio involved so if the engine hits 7000 the drum is rotating the opposite direction at 2.2 times that speed or 15,400 RPM. This is well above the 14K limit seen by the tests TCS had done. That's why it is wise to inspect your Torqueflite after a drivline failure.