in the first scene at the gas station, the guy with the pink hair panics, picks up the gas hose, and then puts it back on the pump. Later as he drives away, you can clearly see the gas hose attached to the car.
the gas hose is supposed to be attached to the car. the whole point is for the car to take off with the hose still attached in order for the gas to splash on the floor. then the big fire starts because of that.