Taking control from a Captain is a big deal - especially if they are also management or very senior.
Readers may recall the crash of Silk Air Flight 185 in 1997. See: https://en.wikipedia.org/wiki/SilkAir_Flight_185
On an earlier flight some weeks before that accident the same captain was trying to lose height on short final by applying full aileron in both directions to activate the spoilers. The F/O who was not culturally bound called for the captain to go around as the 737 was badly unstable. The gyrations of the aircraft were alarming but despite this the captain was intent on landing.
When the captain ignored all the usual SOP warnings, as a last resort the F/O pushed the throttles open under the captains hand leaving the captain with no choice but to go-around. The actions by the F/O saved a sure accident. In this case the F/O did not try to take over control from the captain as he knew this would only exacerbate an already dangerous situation.
training students who in their own country were strongly subject to cultural mores. One of which was unquestioning obedience to authority or higher status.
So true. In the following instance both students were undergoing 737 type rating training in the simulator. The PM was a powerfully built chap from SE Asia with an aggressive personality.
The briefing included a multiple bird strike immediately after airborne causing the failure of one engine. The aim being to return to land at the same airport.
The engine failure was well handled by the PF. After all applicable checklist items had been completed the PF joined the circuit. A fire warning then occurred on the remaining engine. The aim of that exercise was to continue with the planned landing and deal with the fire warning once on the ground, In other words how to deal with priorities.
The PM immediately called for the engine with the fire warning to be shut down; which of course would have been disastrous. The PF wisely disagreed for obvious reasons. This is where culture came to play. The PM flourished the QRH in front of the PF who already had his hands full, demanding the PF follow its instructions which was to close down the engine. Despite protestations by the PF the PM closed down the live engine and fired the bottle. The result was predictable. Afterwards the PM was suitably debriefed by the instructor in no uncertain terms.