The maintenance area is the most dangerous zone. In addition to rats, one of the rooms is home to the Monster. There are only 6 notes in this area, and you won't need any additional items like bolt cutters or wrenches to obtain them. The map below will show the location of all the notes in this area.
Note №1: Rats
Upon entering the maintenance area, you will see the first door boarded up with planks. There will be a warning sign that says "RATS KEEP OUT." Remove the planks and enter the room. On the left side, there is a table with a note on it.
Note №2: Note to a Dead Friend
Continuing down the corridor, on the left side, you will find a staircase. Go up the stairs to the foreman's room. Inside, there will be a table with a note on it.
Note №3: It Hears Me
At the end of the corridor, you will find a staircase leading downward. Descend the stairs and find the hole in the wall where the Monster emerges. There is a note next to it.
Note №4: Where is the Pillbox Lock Key?
Go back up the corridor and find the entrance to the workshop. Locate the entrance to the tunnel. Go through the tunnel, scaring away the rats with fire or distracting them with meat found in the storage room before the workshop. After passing through the tunnel, you will find yourself in front of the entrance to the Pillbox. The note will be hanging near the door.
Note №5: I Saw a Face
On the left side, there is an ammunition storage room. Break the door by any means necessary and retrieve the note inside. Additionally, you can find the key to the Pillbox in the chapel and break the left wall there, revealing a shortcut.
Note №6: Lambert's Journal - Part 1
Nearby is the entrance to the chapel. In the right part of it, near the Confessional, you will find this note.