T. Brooks

"Welcome to the dungeon, Marine; most unexciting place on Mars."

- T. Brooks, upon meeting the Marine

T. Brooks is a minor character in Doom 3. He is a Mars-Sec Admin stationed at a security entrance of Mars City Underground.

When the player meets him, he asks them to equip themselves with a pistol, armor, and a flashlight at a nearby locker. He then tests the radio connection before granting the player further access to the area, and warns the player not to get trigger-happy as civilians are working around the area. He will also send a quick email to a fellow Mars-Sec personnel, Mark Ryan through PDA to help guide the player to their intended destination.

During the demonic invasion, when the player returns to his office, Brooks reanimates as a Shotgunner Z-Sec, forcing the player to kill him. His office can be used to unlock the outside locker containing a Machine Gun and a Shotgun.

Trivia

 * If you discharge your pistol when you first receive it, Brooks will flinch and yell at you to be careful.
 * Brooks seems to be very well known in the Mars City Underground, as he emails almost all the UAC employees in that area through their PDA. This is most likely because he's the only one who can permit entry into the Underground.
 * The Z-Sec of Brooks is actually another Z-Sec already positioned in his office, before the demonic invasion. This can be seen by using the noclip cheat to enter through Brook's office, after he grants the player further access to the level.
 * Surprisingly, despite being an NPC unreachable by normal means, T. Brooks is not a Joe, and if you noclip into the office and look at him, it will show his name. This suggests that at some point in development, the player was meant to interact with him in person.