Get past the lasers, shoot the big guy and take the meat elevator upstairs. To get trough the door, you need to push both switches. Shoot the red light in the strange roof between the switches, and a door opens.

When you get past the door, there is a gap on your left. Jump down there, there is a opening. Don't swim in the red stuff too long.

After shooting some little guys, you push a switch to stop the conveyor belt. Jump on the belt, duck, and crawl inside. On the left is a goodie.