I go through the maze the first time. I get to the door and get that message. Surely I missed some enemies. I go back to the main part of the maze and indeed there remains a few more enemies. I kill them and I go back to the door. Same message. I look to a good to find out that there is a secret room that I didn't check. Surely enough, there are a few more enemies here. I kill them. I go back to the door to get the same message. I go through the maze 5 more times to double check. No enemies. I check a FAQ to make sure I checked every single inch of the maze possible. I turn to GameFAQs and cry for help.
PSN: OGWilson (Killzone 2) XBL: Boss22 Special (CoD4/W@W, Gears of War 2, NBA 2K9