In this page you can see the board for "Rose and Jasper" memory in Get Even as well as information on how to reach the room with a hidden memory. You can also learn about its content.
The evidence board for "Rose and Jasper" memory is presented in the picture above. This location contains many tracks that you can take. You should focus primarily on various documents. Among them you can find, e.g. floor blueprints that look similar. Besides that you can also find, e.g. photos and areas that can be scanned.
In our game the code was 4563 but because of randomness of many of the game's elements you can receive another combination. Warning - Don't try to use a combination because the game won't allow you to do it unless you get all tracks.
Finding this secret room is not that easy as it was with the other ones but it is still not that difficult. During your exploration of the building you must wait for the moment when you can turn right and examine an optional corridor which is presented in the picture above. You can find this area shortly after starting the memory - after you scan the door and reach the first location with enemies (you can take care of them before or after the visit in the secret room).
Inside of the secret room you can find a cabinet that can be scanned. This gives you an SMG that is now added to your arsenal (you can go back to the arsenal in the evidence room inside of Black's mind and take this weapon if you want to use it in other memories).
Inside of the secret room you can also find a TV. When you interact with it you can listen to a conversation between Jasper and Howard.