It's quite likely that from such a height, the victims have already hyperventilated and were unconscious when they hit the ground.
Nice thought, but Albuquerque, NM is 4000 feet higher than this building and those people breath just fine.
Eaker
About 8 yrs ago, a guy fell to his death from the 52 nd story of a Toronto office tower, and the coroner determined that the shock of falling made his body limp on impact, consistent with being unconscious.