The Lounge is an area of the ship where the crew, or any passengers can go to rest and/ or entertain themselves.
Judging by its name, the Lounge can be found on the 10th floor, in the aft side of the ship. It is unknown if it is the only lounge on a P-Fleet cruiser, or if there are others.
The Aft-10 lounge is stocked with cold beer. It is unknown if there are any other beverages, foods, or services available.
The Finnish name Perä kymppi can roughly be translated as 'back ten' or 'butt ten', with kymppi being a slang word for kymmenen.