[BoyTarga]

I've had this happen many times on rollers in a car factory I used to work in. It never got any less scary when you would jump up and off the rollers. You are trained and know that your saving grace that there is really very little energy without the car moving. The inertia in the motor and drvietrain itself won't make the reasonably heavy car go very far. Nonetheless it'll scare the *%&^ out of you.