Rubicon

Brock is demonstrating what you should not do: Using only one hand on the steering wheel and clutching the door (usually a sign of extreme discomfort or fear).

A very common mistake among fourwheelers is to hang out of the door opening while driving. It gives them a sense of control - but all they really see is the front left tire. They are missing all the other information only available when using the "big picture" - the windshield. They are missing what's going to happen in front of the truck and on the far right.

I have also noticed that drivers hanging out of the door/window a lot, have a tendency to keep the the vehicle on the far right of the trail. That creates a very high risk of damage on the right - usually the tires.