Walk out of the elevator, kill whoever is in your way, and jump onto the crate at the bottom left of the Stroggos logo on the wall. Look up and shoot the glowing button to open a portion of the wall concealing a Quad Damage power-up. Jump back onto the main platform where you started and jump cross into the hole in the wall to snag it. Jump back and pick up any health or ammo near the crates you may need.
