Upstairs, talk to Randy. After another cutscene,, you will have to perform a surgery. First, you need to administer narcosis to the patient. Keep an eye on how the syringe moves and point it downwards, as soon as it is in the middle. Then, start spinning the left analog stick, or press the right and the left button in turns. The surgery itself is, simply, a string of commands displayed on the screen, which you need to perform. First, you need to lean the stick to the left (or hold down the LMB), and move it to the right, once (click the RMB). Then, lean the stick to the right (hold down the RMB) and move it to the left, quickly (press the LMB). After the surgery, leave the room.