If the MRGB is allowed to move (as a result of one of the nodal beams or other fixings giving way), it would twist the TR drive out put which could, feasibly, create enough imbalance and drag along the TRD shaft to overstress the boom and cause it to fail.
What is puzzling is that it looks like the rotors take only the top part of the MRGB with them when they separate rather than ripping the whole gearbox out.
Whatever the initial trigger, it rapidly becomes a catastrophic in flight breakup which even the best pilot in the world wouldn't survive.
In a 206, the transmission is not directly connected to the t/r driveshaft - it runs through the freewheeling unit and then the engine. To me, it appears that not only did the entire transmission come out, but maybe the engine as well! Look at this pic and tell me what's missing. That lump there towards the back - is that the engine or just the oil cooler?
