Halo: The Master Chief Collection - Halo 2 - Delighted - Halo 2: Activate Terminal 9 on Quarantine Zone. This achievement is fairly easy to unlock.
All of the terminals can be done on easy difficulty. On the mission Quarantine Zone, you will approach a ship that is apart and on fire.
Enter the ship and there will be a room filled with flood, run past them to the opposite side on the ground floor where the terminal is located.
Run over and interact with it and your achievement should pop! Enjoy!