Beat the DLC! Turns out you were Fettal, or maybe a clone of him, I'm not really sure. once you get up to him, he takes over your body, and the game ends. Maybe I was wrong, and the main character from the first Fear wasn't the first prototype, and Foxtrot 813 was, I have no clue.
Didn't like that ending as much as Fear 2s, though the DLC was fun.