MicKGo:
It would be fair to say, wouldn't it, that The Big Book of Aircraft Accidents would have far fewer pages if every crew did everything that was dinned repeatedly into them every time.
I have to, reluctantly, agree. As I wrote that my thoughts turned to a good friend (and very competent operator) who experienced acrid burning smells in a B747-200, they returned immediately (and landed the wrong way) to HKG but didn't don their masks - the FO passed out shortly after touchdown. THEN he put his mask on!
But I still have grave doubts about the "disconnecting the AP" theory...