I love the time-lapse at the beginning of this video. It shows the "wall cloud" (the rotating, lowering of clouds in the background) well and looks like something out of "Twister." The wall cloud is the point of origin for many tornadoes.
That said, their attempt to get in front of the tornado was foolhardy and could have resulted in serious injury. As it was, their rear window was completely blown out and their front window was seriously damaged.
Amateurs have no business storm chasing outside of one of the guided tours.