I think what you're talking about is "time of useful consciousness". That depends on whether or not the plane was still pressurized, or whether the crew/ passengers were exposed to the altitude, and if there was a rapid decompression. (And it seems they were losing altitude quickly after the brief climb, so the effects of altitude hypoxia may not have been the same as the chart, which is TUC at sustained altitudes.)
When I was an Air Force Flight Nurse, we trained in the hypobaric (altitude) chamber periodically to assess and learn our own responses to hypoxia at various simulated sustained altitudes. One of the most interesting things is how the rods and cones in your eyes respond first to the lower partial pressure of oxygen-- we trained with a "color wheel" and dropped our masks to watch the colors "gray out" at various altitudes, like the colors becoming a black and white photo. We also had to do various tasks, including manipulating toys and other training objects, write, etc.
Here is a wiki discussion of TUC (time of useful consciousness), with a table that correlates TUC/ hypoxia and altitude.
http://en.wikipedia.org/wiki/Time_of_useful_consciousness
However, you also have to factor in the g-forces everyone on the plane was experiencing during the plummet, as well as the attitude of the plane, trauma, panic, etc. If the fall was chaotic, and if most were conscious, just trying to manage your body and limbs is challenging. In the Pacific theater (I was stationed in Japan), we sometimes had to fly between or around bad storms to pick up or deliver an "urgent" patient. A few of the storms were particularly bad. In some of the worst turbulence and "drops", the only thing holding me in the seat was my seat belt. I was helpless to manage my head, neck, arms, and legs. I didn't like that kind of turbulence very much-- sometimes we would hear the "pull up" alarm going off in the C-9 cockpit about 6 feet away. That always made me worried.
