Keycards are dropped when a Boss enemy is eliminated. The player can then pick up the keycard like any other item, taking up 1 inventory slot. When held, the keycard will show a three dimensional arrow on the screen which points towards the vault that it unlocks. The keycard will also produce a sonar sound alongside it.
Trivia[]
There is an unused Shadow/A.L.T.E.R. keycard inside the game's files.
It would have probably been used if The Agency had been turned into Shadow instead of staying Ghost.
Although, it did end up getting used as an Authority Keycard in Chapter 2 Season 3 which dropped alongside Jules' Drum Gun and Jules' Glider Gun.
The Agency Keycard • The Grotto Keycard • The Yacht Keycard • The Shark Keycard • The Rig Keycard • The Fortilla Keycard • The Authority Keycard • Catty Corner Keycard • Doom's Domain Keycard • Stark Industries Keycard