A total of three Yellow Keycards can be found in Haydee. However, unlike other multi-card colours, Yellow Keycards have no relation to eachother; they are simply the default keycard, used as an element in puzzles rather than having an overarching effect on Haydee's progression - although in most cases Yellow Keycards are still needed for certain areas to progress at all.
One Yellow Keycard is needed to retrieve the Magnum in the Green Zone, being found upon a dead Haydee unit's body behind a locked door. The room itself is on the upper floor, on the right just after completing the second four-button puzzle. Inside, Haydee must fend off a Walker and a Slasher before climbing to a ledge above the doorway. A button there will unlock the door to the Haydee body, where the Yellow Keycard can be taken.
A second Yellow Keycard can be found in the Black Zone, alongside the fourth Red Keycard. After destroying four Slashers and solving a button puzzle on the Ground Floor, Haydee can drop down to a room filled with many Haydee corpses, apparently being cremated, and a single Walker. The Yellow Keycard needed to escape the room is found on one of the bodies, along with the Red Keycard used later in the game.
A third Yellow Keycard is found in the Blue Zone, on a Walker body trapped underwater by a cage. A button is located on the other side of the wide body of water; after jumping the gap from a slightly higher point, Haydee can navigate to the button and release the Walker. The card can then be retrieved and used to access a route leading to the Blue Room's Save Station and, eventually, the Orange Keycard.
|Weapons||Pistol • Magnum • SMG • Proximity Mine|
|Tools||Crowbar • Pliers • Power Node • Remote Devices • Screwdriver|
|Consumables||Ammo • Diskette • Medkit|
|Wearables||Armored Vest • Night Visor • Respirator|
|Keycards||Red • Orange • Yellow • Green • Blue • Purple • White • Pink|