Most of the places in Once Human are open to the public, but some areas, like the Underground Bunker near Aidens Hideout, are off-limits, and you cant enter them without a special card. To open this hidden bunker, you need a Bunker Access Card. Inside the bunker, youll find a lot of weapons and storage crates containing valuable loot. It's also a great place to farm Acid by defeating weaker enemies. If youre having a hard time finding the Bunker Access Card, read on to learn how you can get your hands on it.