Amnesia: The Bunker

Foreman Stafford's dog tag can be found next to the body that's up the ladder in the Pillbox in the Maintenance section. You'll need a key, found on a shelf in the confessional booth in the Chapel, just down the path and to the left from the Pillbox. As soon as you pick up the key, shut the door and hide in the booth, as the beast comes in afterwards.

His dog tag has a code on the back of it that opens his locker in the Mission Storage section, where you can find the Wrench.

Watch out in the Pillbox too, there's a sniper that fires at you. And the section beforehand with the rats in the tunnel can be tricky, I recommend tossing meat bait towards the middle of the tunnel and using a molotov to kill the rats as they're bunched together.