You’re just about done picking up everything you need in Resident Evil 2’s Sewers — you even got a fun new Chemical Flamethrower out of the deal. You’ve found (or seen) all of the chess-themed Plugs you need to open the door in the Monitor Room, so it’s time to go do it and rescue Ada. We’ll even take a detour along the way to upgrade your Magnum.
Objective: Use the plugs to open the door
From the Supplies Storage Room, weave your way back through the gross-bergs and head back toward the ladder at the east end. You’ll have to fight a few G-Adults on your way, but you’ve got you shiny new Chemical Flamethrower to help you — it’ll take about 100 units of fuel to down one, so don’t waste fuel.
Water Injection Chamber to the Workroom
Instead of heading straight back to the Monitor Room, let’s take a quick detour to use that Sewer Key we picked up.
At the top of the ladder, turn right and loop around to the far side of the room. Head back up to that Y-shaped room and drop into the sewer’s Lower Waterway. Keep heading east and take the Workroom Lift up to the Workroom.
Exit the Workroom and cross over the bridge on your left. Use the Sewer Key to open the room on the far side and grab the High-Grade Gunpowder and Gunpowder (Large).
Workers’ Break Room
Head south across that bridge again. Grab the Rook Piece as you pass — this is the last piece you need for the Monitor Room Puzzle. Take a left after the bridge and open the door to the Workers’ Break Room.
Pick up the Gunpowder, Handgun Ammo, and the Jazz Festival Flyer. (The circled letters are the combination for the locker in the Control Room.)
Face the cabinet on the wall. Interact with it to shove it out of the way. This will reveal an elevator back to the Underground Stairs. Take it up and turn to the left when you get to the top. Use the STARS Badge — you’ll probably have to examine it again to retract the USB port — to open the weapons locker and get the Long Barrel (Lightning Hawk) upgrade for your Magnum.
Climb back up to the Secret Room. Use the T-Bar Valve Handle to open the door back into the Main Hall.
Make your way back to the Darkroom — the Police Station should be mostly empty at this point — and use the ‘Hiding Places’ Roll Film in the sink. You’ll get two pictures. Those show the locations of two new items.
Make your way back to the Press Room (to the east of the Main Hall). Open the drawer in in a table to the let of the podium with the microphones. You’ll find some Fuel for your Chemical Flamethrower.
Turn left as soon as you enter the STARS Office, and go into the office within the office. Open the drawer in the desk there. You’ll find a Wooden Box. Examine it in your inventory and you’ll get the Red Dot Sight (Lightning Hawk) for your Magnum.
Back to the Control Room
Retrace your steps all the way back down to the Workers’ Break Room. Exit and cross over to the Workroom (make sure you grab the Rook Plug if you haven’t already). Drop back into the Lower Waterway and head west. When you get to the fork, take the right side. Fight past any G-Adults that have shown up. Continue up past the Cable Car Platform and into the Control Room.
Enter the combination you found — SZF — at the locker to find some MAG Ammo.
Monitor Room puzzle solution
Drop back into the Monitor Room again and head for the U-Area. You’ve got all the Plugs now, so you just have to rearrange them. Standing next to the door, face the bulletin board at the back.
On your left, from left to right, place the plugs: Bishop, Rook, Knight.
On your right, from left to right, place the plugs: King, Queen, Pawn.
The Knight and the Pawn are in the panels with their pictures. You have to move the Bishop from where it’s already placed.
Main Power Room
Once the door opens, head down the stairs and grab the Blue Herb and the Green Herb. Cut to the left to find the switch to open the door to Ada. It, unsurprisingly, doesn’t work.
Turn around and head to the Main Power Room. Grab the Red Herb, then head to the panel with the switches. Throw 1, 2, and 4 to power up the door.
G (Phase 2) boss fight
When you go to exit the Main Power Room, that boss from before, G, will show up again. Keep running around the room, avoiding the fire and his giant claw poking through the ceiling. Your goal is to avoid him long enough for the way out to open up. As soon as you can sprint past him through the door he came in through, do it.
Follow the walkway on the other side until you drop off it. Run around the shipping container and break to the left. As soon as you get to the control panel, hit the button to swing the crane away.
Sweep the platform you’re on for a Combat Knife, Flash Grenade, Handgun Ammo, and MAG Ammo.
Your goal is to get G to take a knee, then swing that shipping container back into him. Use the whole platform to avoid him until the crane stops moving, then pump everything you can into him until he falls. Sprint over to the panel and hit the button. Repeat the process one more time until he’s definitely defeated forever and won’t ever come back again.
Use the wreckage to cross off of the platform and climb the stairs back up toward the Garbage Room. Throw the switch to find Ada.
Head to the Lab
Escort Ada back up to the Monitor Room. While you’re here, you can visit the Typewriter and Item Box, then keep heading around to the Cable Car Platform. Pull the lever on the console to head down to the NEST.