Stand Down is a campaign achievement/trophy in Call of Duty: Black Ops. It requires the player to complete the singleplayer campaign on any difficulty. In the natural progression of the game, it is unlocked after "Redemption" is completed.
If one uses the "3ARC UNLOCK" code in the main menu's computer terminal and unlocks all campaign levels, this achievement will be disabled and will not activate once "Redemption" has been completed. This does not affect the PS3 trophy, however.