The Medical Block was an area of the Ozymandias colony ship. It was located next to the Housing Block. The crew were treated here when diagnosed with radiation poisoning. It is one of two rooms impossible to enter. It says the formation change has to proceed to unlock the door. After the nformation change, you cant get past the giant fans. When you are in 0-G, you can now get to the room, but now it seems the Lobby room to get there is now locked in order to keep energy.