Breaking Quarantine is an achievement in Halo: Combat Evolved Anniversary that is awarded for escaping the Flood containment facility on the level 343 Guilty Spark in 21 minutes or less. It is represented by an analog clock with the number "21" beside it on top of a purple octagon.
The Achievement is worth 25 Gamerpoints.
- The name of the achievement is a likely reference to the story Breaking Quarantine from the Halo Graphic Novel, as the plot of it (Sergeant Major Avery Johnson escaping from the same facility) effectively matches that of what the achievement requires.
- The fact that the player must escape the facility within twenty-one minutes is a reference to the number seven, as 21/3 = 7.