Supplies Storage Room Puzzle
In the Lower Sewers, after getting through the Bottom Waterway, you’ll come to the Supplies Storage Room. Pick up the Queen Plug and King Plug and use them on the doors. You just have to alternate between using one plug or the other, There’s also a small armory with a weapon here. The important thing is that you make it out with both the Queen & King Plug in your inventory as you need them for the next puzzle.
Location: Sewers (Lower), Supplies Storage Room
Solution: Take Queen Plug and put it in door on right side. Go upstairs to get King plug and put it in the door to armory to retrieve weapon. Take out King Plug, take out Queen plug. Put Queen Plug where it originally was. Then put King Plug on the side where you came from. Finally, retrieve Queen Plug and backtrack to King Plug. Take out King Plug and you should be back at the start of the Storage Room. Now backtrack to where you came from (Monitor Room).