While trying to get away from a truck, Eddie will pull the car off the road and drive down a track. A short time later he will hit something. There will be a discussion about whether it was a person or a walker and it is decided that someone should go outside to check.
You will play Rock, Paper, Scissors to decide. You will want to win two out of three to get the following achievement anyway, so if you lose a second one, quickly quit out and reload. Don't worry if you get a draw.
After that Eddie will go outside to check and throw you the keys. Move the seat but you won't be able to see. Turn on the interior light and you will see them. There will be a brief fight with the man from the truck and you will drive away once you have started the car and put it in drive.
For leaving your friend out there, you will be rewarded with the achievement.