Setup - Get power and pack-a-punch. Now turn on Klaus. Now get the blacklight.
Code - Make sure you have the blacklight on. Go to the Garment factory and with the black light looking all over the walls until you see two green numbers. Remember all the numbers you see and when. The next place to get numbers is in the Service Passage. The final two numbers are at the Grocery Store. Now head back to Hotel Room 305 that you needed for Klaus. go to the safe in the corner of the room. Now put in the numbers in the order of places that was listed. For example, if there was a 17 in the Garment Factory then you would put in 17 to the first dial. Once you have them all correctly in there it will open and you will get the free CRBR-S.