In Primary Excavation(right before you fight the Cyberdemon), stick to the left wall so that you don't trigger the cutscene. You will see a brick wall that has the id Software logo on it. Click on the logo using your mouse, and the brick should move back. The wall on your left will open, giving you access to a PDA containing thank you e-mails from the staff.
Contributed By: Naru2005.
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