Jayour and SLY SCORPI0N wasnt too clear in my opinion but I found a guide that is.
Similar to the “Did anyone survive?” achievement except this has to be done through the leaderboards. At the main menu, choose "Leaderboards", then "Ignition" and press "A" to start the story/campaign. Once you've successfully finished one of the routes A, B, C or D, your time will be sent to the leaderboards unlocking this achievement.
Note: This has to be done in one sitting! You cannot quit in the middle of the game and continue where you left off earlier. The game doesn't autosave after a completed mini-game! Of course you can pause the game and continue later on if you leave your console turned on
Credit to the author, Trikke (not sure if he/she is a TA member or changed their gamertag), of this guide: http://www.xbox360achievements.org/game/dead-space-ignition/...