I saw an FBI training video and yep, they said not to go anywhere with the perp. They demonstrated gunning the gas, slamming on the brakes, and in one fluid motion taking off the seatbelt and rolling out the door. The BG can't stop physics so the gun will NOT stay pointed at you, which probably gives you about 1.5-2 seconds to take action. And since he probably hasn't put on his (well, technically yours
) seatbelt, he should be stunned just long enough for you to make your escape. It was pretty cool how they showed it. No matter how hard the BG tried to hold the gun pointed at the victim, he just couldn't do it!