Steve.. I have watched several explanations by experts... and by Biles herself. That 'mistake' you refer to in the vault was her first indication there was a problem. She didn't know exactly why she couldn't control it, but after tests away from the competition, she found she could do forward and backward flips ok, but when she tried to 'twist' in the middle, her sense of location and timing was not there.... thus she landed WAY off in that vault. Because she does some of the most complex and difficult vaults and mat routines in the business, lack of control of the tiny details of location during twists in the air is flatly dangerous! Most of her skills WERE ranked high because they included twists. When she finally decided to do the beam, she did a simpler dismount than originally planned... thus lowering her possible score.

   She remarked that it was weird to find her 'wiring' didn't work right any longer.
   After the career she has had, it is not fair for ANYONE to suggest she just panicked or succumbed to pressure & fear...etc.
I watched a golfer once suffer from vertigo in the middle of the U.S. Open... and I have had it briefly myself. Something to do with the inner ear canals. Perhaps that was involved with Biles. *shrug*



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