Those guys aren't too bright. First off, them both flooring it in reverse is a terrible idea. If that guy in the TRX makes it back up he'll be coming up so fast it would take a small miracle for him to not hit that other truck, or worse one of those dumb-dumbs standing too close.
I've been off roading and Jeeping many times and one thing that sure makes a big difference: tires! He was asking for trouble starting down that path with stock TRX tires.