For this you will need 4 players.

Get around 3,000 points each, open all the doors and use the box.

Now go to the teleporter room with the large tanks. Have one person in the right hand side (with your back to the teleporter) and another in the left hand side room.

Have the other two aiming at the doorway where you just came from. Now place bouncing bettys in the left hand side room and camp there. When you get over run just teleport.

You and the others are aiming for these guns: wonder waffe, ray gun and a type 100 (you chose the rest).