This is earned for finding optional collectible #5. If missed on the first run, you can "Play Episodes" and select specific parts of the Episode in order to find the missing optional photos through collectibles mode
. The following collectible is described and can be seen in the video below at 4:05:
Once you reach the hotel, and leave the washroom, look inside the drawer of the bedside table in the middle of the room. Pan to the left to spot the casino token, and take it.
Getting all 6 collectibles in this episode will also reward you with the following: