C4 Detonator and Battery locations in Resident Evil 2 are your next objectives after you've visited the Courtyard and Art Room.
Doing so allows you to reach the third and final Medallion location.
Looking for something else? Visit our Resident Evil 2 walkthrough for more help.
Where to find the C4 Detonator location
You have several new items - the Cutting Tool, Round Handle from the East Office and the Weapons Locker Key Card from the 2F Art Room - so it's worth going back to the West Wing. Go along the 1F, retracting your steps from earlier through the Reception, sprinting down the corridor that's now flooded with zombies.
When you reach the Operations Room again, you can now enter the door to the south by using the Cutting Tool, letting you explore a new room. Note at this point, you should be told you can safely dispose of the Cutting Tool now it's been fully used, as indicated by the small tick. Select it, then dispose, to ditch it from your inventory.
On the desk is an Electronic Part. Examine it, turning it around and pressing the button prompt, to change it to the Detonator (No Battery). This is for the 3F West Storage Room - but as suggested, it's missing a battery.
Elsewhere in this room there is a Green Herb, various ammo, and a hint at a locker code on the wall - CAD. Remember this, as we'll be headed in the direction of that locker right now.
Where to find the C4 Detonator Battery and how to use the Battery
When ready, head west into the corridor outside the Safety Deposit Room and West Office. Head into the Safety Deposit Room and use the Weapons Locker Keycard at the end to get your hands on the Shotgun (as Leon) or Grenade Launcher (as Claire).
This can down a zombie in a blast or two, but we'd recommend saving it for emergencies and more powerful enemies, especially as you can sprint past most zombies, or take them down with the masses of Handgun ammo lying around.
Head north-west, up the stairs to the 2F locker, where you can open the locker with the Locker Code provided earlier (there are Shotgun Shells or Flame Rounds inside, depending on who you are playing as) and able to use the Round Handle to stop the steam blocking the way into the Shower Room.
There is nothing else here of interest apart from some lockers with some ammo inside. Proceed through to the corridor at the far west end of the 2F - and make sure you have the Shotgun (Leon) or the Grenade Launcher (Claire) and some health items handy.
How to kill Lickers in Resident Evil 2
Grab the ammo on the left, and get ready to face your first Licker. These creatures are blind, so they won't see you if you are nearby, but they will react to sound. You can safely walk around, but that will still slowly attract them to you. It means you can pass them if you have room, but in a tight corridor like this, a fight is the best way to deal with them once and for all.
Otherwise, if you have a Flash Grenade, that is an excellent way to daze them before running past.
When fighting with these guys, keep your distance to avoid its tongue and pouncing. If you are playing Claire it's much easier as the Grenade Launcher works at range and takes just a couple of rounds, but as Leon, it's not as simple, requiring you to get much closer with the Shotgun. Keep calm as it's scurrying around and it'll be downed in no time.
When done, enter the STARS Office door halfway down the corridor. Enter the office to your left, and get the Battery from the desk - combine it with the Electrical Part / Detonator (No Battery) from earlier to create the Detonator.
There's also an Internal Memo File from the far end of the room, giving you the Safe Code combination for the 1F West Office, which will give you a Hip Pouch for more inventory space. Otherwise, the STARS Office has a PC you cannot use yet, and an assortment of consumables such as ammo littering the room.
Playing the DLC? Check out our list of Ghost Survivors Mr Raccoon locations. Elsewhere, our full Resident Evil 2 walkthrough explains every aspect's of Leon and Claire's campaigns, including C4 Detonator and Battery locations, Heart Key location, how to stop Mr X, the Clock Tower puzzle, Sherry block puzzle in the Orphanage, the Power Panel Parts puzzle solution, how to escape the Incinerator and the Chess Plug puzzle solution. Not only that, we also provide all Locker Code solutions, the Leon Desk puzzle solution, all Resident Evil 2 Safe Codes and Portable Safe solutions and the Hiding Place locations.
How to use the C4 Detonator
Time to make use of that Detonator. Head back through the showers and up the stairwell to the 3F, and head to the West Storage Room. Find the C4 on the south side of the room, and use the Detonator.
Stand back to avoid the explosion, and head through to find the Maiden statue and third Medallion puzzle.
Once collected, a Licker and a zombie will emerge when you progress back through the West Storage. You cannot outrun them easily as the way to the Library has been blocked by a fallen locker, so fighting them will be your best bet. When cleared, head through the Library back to the Main Hall by moving said locker.
If you haven't already, it's worth using the Spade Key on the west side of the Main Hall 1F, providing access into the West Office, and allowing you to dispose of the Spade Key.