I was thinking the same thing the first time I looked at the video. I know the West Side Highway like the back of my hand. I probably would have done exactly what you described, if I could.
The altercation started near 125th St on the West Side highway. In two minutes, the driver would have been at the exit to cross the George Washington Bridge. But, he turned off to go back into the city, and the street traffic.
If he had gone across the bridge and the altercation happened ON the bridge, there is so much police presence as vigilance of a terrorist attack, that the Bridge Police would have gotten there sooner.
Or, once the driver crossed to NJ, the attack, which started in NY, would have become an interstate crime, and the FBI would now be involved.
However, take a look at this close up picture below, which I posted yesterday, of the SUV driver, down on the ground and surrounded by two bystanders, with their arms out, holding the area around the SUV driver in a "Do not cross this area" pose. While the riders are on their bikes, getting ready to drive off. These bystanders could have intervened, and the SUV driver only received the beating and slashes he got, instead of being beaten to death or knifed to death.
Had the driver been stopped on the George Washington Bridge, I doubt other people in the cars would have gotten out of their cars to help him. There also is only highway on the other side of the bridge. No pedestrians. He was driving on slashed tires that made his car hard to drive forward, let alone maneuver back & forth. He wouldn't have gotten far across the bridge or on the highway. Being beaten there, with no bystanders stopping the riders, could have been fatal for the SUV driver. Turning onto busy city streets may have been the best thing the driver could have done.
Warning: Picture link shows graphic violence. Not for the faint of heart. Open at your own risk.
http://thenypost.files.wordpress.com/2013/09/biokiegang1.jpg
.