Doom 3 Easter Egg - Hidden Pda - Message from Creators

As you're wandering around the tunnels on the way to the final boss very near the end of the journey you'll have the opportunity to go to the right to face the boss or left. Go left. You'll soon reach a dead-end but you should notice that the id Software logo is on one of the blocks. Crouch down, approach the logo block and click it like a terminal interface. The block will recess and you'll hear a wall moving away to your left. Make your way over the little lava pool and approach the altar to receive the hidden PDA from "id Creators". Enjoy!