BWV 988
With severe buffet at 02:10:57, the Captain would have felt it too..........
I think that´s not a too difficult question to do some guessing answer.
While expieriencing buffet while flying through bad weather seems a normal and often expierienced event, buffet due to approaching stall sure was the first time in their life in an aircraft.
And even in the simulator
AFAIK stall approaches are not trained with nose high attitudes but beginning from decelerating in straight and level flight.
The mindset of the complete crew was not orientated to a loss of control situation in the classical sense, meaning stall, but in the sense that the aircraft does not react like expected. "What´s happening? We dont know......"
BWV 988
He must also have noticed an unusual, continued climb >1/2 min before that.
In a full motion simulator we can feel climbs and descents, acceleration and deceleration along the longitudonal axis by just tilting the box. So pilots are not used to base their judgement on the bio vestibular system when lying in the crew bunk or being on the way to the cockpit.
When pitch is established (lets sáy 10°) and the aircraft is decelerating, the body would feel a descending sensation even if still climbing.
BWV 988
So why didn't he return to the flight deck earlier than 2:11:40, and should he even need a briefing from PNF to connect those dots?
Answer see above.