People who are falling to their deaths will do anything to ease the impact. I don't think anyone in that scenario would stop and think, "wow, me flapping my arms is obviously not going to work" due to the fact they only have a few second of life left and their brain is working overtime. They're going to do it regardless. I find it hard to believe that you would just stay still and hit the ground like a plank of wood. Even after you realized that you are going to die and there is NOTHING you could do to save yourself.

