Rob I think since this is a full blown race car, the fire extinguisher was the white smoke/fumes you saw after the fire. The lines for the extinguisher run with the roll cage, but it only goes off in the inside to protect the driver. Look at the guy run to the door and flip the switch. I think it didn't work all that great since it had no doors or hood therefore the smoke goes everywhere instead of being contained and extinguish the fire.

Let me translate what I can understand... before 1:45... "now be sure to roll the car over the flame to melt things and spread out the damage more evenly... see isn't that nice?" "hey let me fan the gas fire on the engine with this tee shirt"

well, they did get the fire out before the extinguisher arrived