To infiltrate the BioVida Facility in Angel De La Muerte in Far Cry 6 go into the building on the east side of the BioVida facility and climb it all the way to the roof.

Use the walkway to get to the main building, climb the ladder, shoot the lock on the door and go inside.

Follow the corridors around shooting glass and unlocking doors using the red consoles as needed to keep advancing. Eventually you will end up in a dark room with a prisoner.