Two rules invloved here:
Rule #1: NO PASSING ALLOWED.
Rule #2: See Rule #1.
For practicing this type of ride, lay out a number of 2x6's, not in a straight line, cover liberly with marbles, and then ride up and down w/o slipping off.
I noticed the the bikes are equiped with GPS so that the survivor can mark the the location of the non-survivors body for pick up by the helicoptor crew.
Not sure I could even walk that trail, much less ride it.