There are plenty of cases where people have made a "little movie", in circumstances where some might expect everybody to be either in shock, or legging it, or both. When the London Underground was bombed recently, several mobile phone movies were made.
It would seem completely possible that everybody sitting in a section of the airframe might have walked out - the movie indeed shows this. It also shows the overhead lockers still in place (though open) so that airframe section did not come down that hard.