The Scorpion is a SMG and it can be found on the first floor of the East Wing (with scientists running around). There is a locked room. It has doors on either the main lobby side, or the small hallway along the back heading towards the bathroom. The doors will only open for guards or scientists. Either sneak in behind one, or kill/tranq/knock out one and drag him up to the door. Inside you will find some ammunition and the Scorpion.