Ki and Gil enter this room through the door at the bottom-right of it. It contains four Green Slimes and twelve Black Slimes (which take ten hits to kill).
The first key at the top-left of the room opens up the door at the top of the room, the second key at the top-left of the room opens the door at the top-right of the room, and the key at the bottom-left of the room opens up the aforementioned door at the bottom-right of the room. Remember this now.
The door at the top of the room leads to Spoils Room (Room Pass: 9C2) - while the door at the top-right of the room, like that one at the top-right of Observatory, leads to Shunned Cavern (Room Pass: SVY), and the aforementioned door at the bottom-right of the room leads back to Observatory (Room Pass: YC9). You should only remember the first and second of these Room Passes, as the third of them will not be of much use to you now.
