but the Lauda Air 767 that had a reverser deploy on climb out of Bangkok in 1991 was deemed by Boeing and the NTSB to be recoverable if the crew had acted quickly enough.
Thread drift I know, but I remember reading that Lauda 767 accident report and the published tests that done after the event. The test report stated that the crew had four seconds to recover from the situation once the reverser deployed before control was irrevocably lost due aerodynamic forces. Keeping in mind it was at night and at the climb speed at the time which was around 280 knots IAS, the effect of reverse on one engine at that speed was catastrophic.
The rate of roll with one engine in full reverse would have inverted the aircraft extremely quickly. In any case there is a safety factor with inadvertent reverse in flight in that the throttle automatically closes to idle which in theory would make the rolling action less severe.
Assuming that safety factor did cut in with the Lauda 767, four seconds to get the aircraft straightened up after an extremely rapid roll and extreme nose down attitude was probably impossible allowing for the surprise factor. Also in those days very few airlines practiced unusual attitude recovery on instruments in their simulators so the Lauda pilots were possibly ill-equipped to get out of that event.