The Quake room, located in the Wasted Garage, can be accessed only after you press three well-hidden red buttons in the area. If you recall, the Wasted Garage is where you were asked to retrieve a distributor cap item during an earlier mission. It is recommended that you complete said mission and re-enter the Wasted Garage from the back entrance.The three buttons are difficult to find: one is located under a night stand, the other between a fallen file cabinet and the window, and the last behind a red tool cabinet. Each makes a Quake-like sound and glows for an instant when pressed. After all three buttons are activated, a hallway marked by a red Quake symbol leads to some stairs and to a portal that takes you to the hidden Quake room. Inside, you'll find the Shambler Plush in the center. To leave, you must step on the tile in the area from which you came.