There are multiple locked locations in Far Cry 6 that contain worthwhile weapons and supplies you can steal from the military to use against them and free Yara with Libertad. For example, there’s a bunker you can find underneath the Cortina Weather Station in Costa Del Mar that contains an FND Cache, along with other valuable supplies, but it’s locked behind a sealed door. This guide details where you can find the key to unlock the door and access the contents inside the bunker.
The key you want to find at his military location is over by the east side of the base. Given the chaos, we secured the base before grabbing the keycard, and we’re unsure if it dropped from a notable NPC guarding the base or was on top of a crate. Regardless, head to the east side of the base, and investigate the containers there. Once you find the keycard on top of a box or loot it off a high-ranking guard, you can head underground.
The entrance to the underground portion of the Cortina Weather Station is over by the southeast part of the base, next to the vehicle pickup location, if you’ve captured the base. Proceed through the door, and make your way through the underground passage. You won’t be able to enter any of the metal doors in these catacombs until you head down some stairs and find a locked door to the left of you. It should have a sign next to it that reads “FND Armeria.” You’ll be able to open up the door using the bunker keycard and obtain the FND Cache.