After being lost on this one for a minute, I finally figured it out. It's not really a secret, so I don't think it really classifies as a spoiler. But it is easy to miss out on being able to do.

At the very beginning of the game you need to grab the lighter, then move to the adjacent room that has the first key in it. After grabbing the key the game triggers a script to lock the front doors behind you. This is your queue. Immediately after grabbing the key RUN out the front doors of the Orphanage before they shut and lock trapping you inside. Then run over to the gate with your truck behind it and you'll unlock the achievement. I suppose this also counts as an ending, as it ends the game.

Hope that helps anyone that wants to earn it.