A button in an office has to be pushed which opens a door and delivers Personality Cores to the ship. The Borealis has a cameo in 'Portal, the Flash Version'. The ship was built to be extremely durable, one intention of the ship was it being an icebreaker ship so it wpuld need a lot of durability to survive that. However the Borealis didn't have access to the Arctic from the drydocks. It is widely believed that the ship contained a portal device, on a much larger scale than than the ASHHPD, though it likely doesn't work the same as the Portal Gun due to the fact that it moved from the drydocks it was built in into the Arctic, but the Portal Gun requires basic access to both locations. All that remains in Old Aperture of the Borealis
