Now, if you see the lights dim, and hear a weird noise(you'll understand what I mean when it happens), this means the scientist is coming. Wherever you are, get to the middle level of the map, and get to the opposite corner of the raised platform to where the stairs are. You'll know the scientist is after you if you can see him, so if you can, swap to your worst gun. Now it's your job to stay away from him, just keep running avoiding him. Your team mates will all shoot at him(you'll see him as a cloud of red mist). You'll know you hit him if your score goes up. It takes a LOT of bullets to kill him so be warned. If he gets you, don't worry, shoot him straight after he takes your gun, and get back to the middle level to help your team mates try and kill him. When you kill him, anyone who has had their gun stolen gets it given back & you get max ammo + a Sale.
A sale means that all locations of random box appear, and it only costs you 10 cash to buy it. However, after you kill him the next round starts so don't be caught off alert by this, and instantly get to defcon 4 to make your exit.