Inside Toluca Prison, James will open up a door with a Headless Serpent, which introduces him to the Serpent Section. Completing this area is a critical part of the Scales puzzle out in the Yard of Toluca Prison. To help you out, here's how to complete the Serpent Section of Toluca Prison.
How To Complete The Serpent Section In Toluca Prison
After entering the Serpent Door, make your way forward until you reach the Guard Room, where you can find a Syringe, a note about the generator, and some other goodies.
Most of the cells in this area are currently locked. For now, head down the hall and into E4 for an interesting photo Memo. You can also grab some Handgun Ammo from the unlabelled room just north of E8.
Continue west down the hallway into the unmarked room. Cells E10 through E20 are locked for now, so your best bet is to head north into yet another unmarked room. This one offers a Save Square.
Where To Find The Medium Weight
Inside the Witness Room, discover a generator. Flip all the switches on it until you’re in the red zone, allowing you to completely overload the system and trigger the electric chair in the room next door.
Head on over to the Death Chamber next door and grab the Medium Weight from the Electric Chair. Open the door you didn’t come in from, and you’ll end up just south of the Death Chamber.
Overloading the generator opens up all of the cells, so grab what you can from cells E1-E9, including some Handgun Ammo in E3 and a Health Drink in E7.
Once you’ve got everything you need from the cells, make your way to E10 and grab some Shotgun Shells before slipping through the crack in the wall into a new unmarked room just to the right of the room marked with the question mark.
In this next room, grab the nearby Handgun Ammo and read the unsettling note. In the next room - the one marked with the question mark - grab a Health Drink from a desk drawer before opening up a locker to discover some Rifle Rounds. Then, grab the Armory Key from the back of the room.
Head through the north door back to the Witness Checkpoint, then head through the door right in front of you. It was previously locked, but James will unlock it now. You’ll end up in the southwest section of Toluca Prison’s 1F.