Psi-ops Easter Egg - They Live Hidden Reference

IMPORTANT: NEED TO UNLOCK ALL PSI POWERS BEFORE DOING THIS EASTER EGG! TO UNLOCK ALL PSI POWERS; Highlight 'Extra Content' in main menu and press R. A screen will pop up. Enter the code 537893. Select cheat BEFORE starting mission

After fighting the dead in the cemetary go into the control room and activate the Aura View power. Look at the monitor on the wall and you will see the message "OBEY" wich is a referance to John Carpenters movie "They Live" where the same message is seen on billboards using special sunglasses.