1. SAVE YOUR POINTS! You got to have alot of points cause you need the box to move and enough to buy a perk and random box.

2.get the box to Comm Room or Docters Quarters

3.when the box is at either places wait for the perks-a-cola- machine to choose a perk.

4.(Now this is where the glitch comes in) Have enough points to buy that perk and the mystery box. Get the box and quickly buy a perk. WHILE YOUR PLAYER IS DRINKING THE SODA pick up your weapon(you gotta be quick)

you will get the perk and the 3rd gun.

A good thing to do is have another person protect you or make a crawler.

i dont know if this works with 4 guns but if you try comment!