deanm
The cabin altitude during the cruise would have been about 6000 feet. The masks will deploy when the cabin altitude reaches 14000 feet. Within a few seconds of the missile strike the cabin altitude would have increased to the aircraft altitude of 33000 feet and the masks would drop. So within 5 seconds of the cabin being pierced the masks would have dropped, probably more like a couple of seconds.
Rapid depressurisation is extremely painful on the ears and a shock. The noise from airflow and engines and the force of the airflow itself would be a massive shock and the deceleration very debilitating, possible broken necks etc. Negative panic would probably ensure that most people did nothing and just froze. They would be unconscious in about 30 seconds. If someone did have the presence of mind to grab a whirling mask and put it over their mouth and nose it might keep them conscious. However if the aircraft had broken up there is a good chance the ring main would have been severed from the passenger oxygen bottle which is towards the rear of the aircraft so they would not get any oxygen anyway and would become unconscious within 30 seconds or so. So to me if someone had put a mask on it does not necessarily mean they were conscious all the way down, it just means they had the presence of mind to put a mask on within 30 seconds of the depressurisation.