I view the initial collision like this:
Biker moves infront of SUV. Bike slows down gradually. SUV is concentrating on the bikers to the sides/behind him. SUV slightly bumps the bike (IMHO this could have been enough to knock the biker off). Bikers force SUV to stop. SUV driver doesnt get out of vehicle (probably getting abuse already from other motorcyclists). Bikers start attacking SUV (cont see this though so dont know if it is true). SUV driver fears for life and his natural instinct is to protect himself. SUV drives over bikers. Bikers give chase.
SUV is held up by white car which bikers have forced to stop. Bikers attack SUV. SUV speeds off again (knocking down another biker). SUV speeds through built up area. SUV gets blocked by traffic. Bikers attack SUV. SUV tries to push the car infront out of the way but doesnt succeed. (Video stops). SUV driver gets beat up by bikers.
If I was the driver, after the initial collision I would have probably wound down my window and tried to speak with the biker that had been hit. However, it is unclear what was happening initially. If I was fearing for my life, of course I would drive through the bikers. Its a natural instinct.
I think the driver did the wise thing going into a built up area (lots more witnesses and he might have been looking for a police officer). I think the bikers took it way too far. Surrounding the SUV and being twats to other road users will never end well.