Sentinel wall

The Sentinel Wall is a massive wall built by the Sentinels surrounding the Quarantine Zone around the Library of Installation 05.

History
The Wall appears to have been designed to keep the outbreak of Flood around Delta Halo's Library contained within the Quarantine Zone. It is honeycombed with many tunnels for the Sentinels to travel through. Sentinels and Enforcers keep the Flood contained, while Constructors keep repairing the damage that the Flood inflict on the Wall. It is possible that there is constant battle in the Quarantine Zone, as in the level of the same name, Flood and Sentinels are seen in many instances fighting each other.

Battle of Installation 05
Despite the efforts of the robotic keepers, the Flood were released when the Arbiter penetrated the defenses and deactivated the containment shield around the wall. It is unknown if such a structure exists on other Halos. During the battle on Installation 05 the Arbiter was sent into the wall to deactivate the shields keeping the Flood in the QZ in order to let other Covenant forces fly over the wall towards the Library. It is possible that this is what caused the Flood to be able to capture Covenant craft and attempt to use them to escape Halo, as seen in Ghosts of Onyx.

Trivia

 * A section of the Sentinel Wall can be seen on the Halo 2 Multiplayer map, Containment, a multiplayer map only featured in the Halo 2 Multiplayer and Halo 2 Vista map packs.
 * It is unknown whether the other Installations have this feature as well.

Related Articles

 * Forerunners
 * Battle of Installation 05