Unto Dust
Unto Dust is an achievement in Halo: The Master Chief Collection. It is awarded for activating the fifth Halo 3 Terminal on The Covenant. The achievement is worth 5 Gamerscore and can be unlocked on any difficulty. The player must scroll through and access both parts of the terminal to unlock the achievement.
Location
Once the player will be able to access the second terminal once they enter a Hornet for the first time; it is in the second tower (the one that the Sangheili has already disabled). As the player heads toward the tower, the Arbiter will remind them that Tower 2 is already clear. The Terminal is in the main hallway of the structure, flanked by three dead Sangheili, opposite the only (locked) door.