There is a secret locked door inside The Base, where you will reach during “The Eye of the Earth” main quest in Horizon Forbidden West. This guide shows the location of the secret locked door in The Base and the door code.
The Base: Secret Locked Door
You will reach The Base during “The Eye of the Earth” main quest. Enter The Base and from the main hall, go downstairs through the door as shown in the picture below.
Continue straight ahead until you reach the server room. Go through the door on the eastern side of the server room as shown in the picture. Enter the room and then crawl into the vent straight ahead.
After you drop done from the other side of the vent, you will be on level 2 of The Base as shown in the picture below. Here you will find a secret locked door.
The Base Door Code
To be able to unlock this door, you will first need to talk to GAIA during the “The Eye of the Earth” main quest and ask her questions to unlock the “Established the Base” trophy. Without unlocking the trophy, you won’t be able to unlock the door, even with the code.
To get the code, you will have to read 4 Datapoints around the Base. From these four data points, you will get some numbers. Combine the numbers to get the code.
Datapoint 1: 9
Datapoint 2: 626
Datapoint 3: 11
Datapoint 4: 8
So, the Door Code is 9626118. Enter the door code to unlock the door.
Unlock the door and go inside the room. Unfortunately, there is nothing very exciting inside this secret room. Here, you will find 5 Datapoints as shown in the picture below.