Quarantine zone (location)

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The Quarantine Zone was a perimeter surrounding the Library of Installation 05, located within the Sentinel Wall. The Sentinel Wall, along with the containment shield it projected, had kept much of the Flood from spreading during the eons-long outbreak on Delta Halo, allowing Sentinels to contain the violent parasitic force. The shield's deactivation by Arbiter Thel 'Vadamee during his search for the Activation Index in 2552 ultimately allowed the Flood to overwhelm the Sentinels' defenses and thus move freely about the ring.

Overview
The area was guarded and patrolled by various Forerunner constructs, ranging from the small but necessary Constructors, to the standard Sentinels and Sentinel Majors, to the titanic Enforcers. The Quarantine Zone was apparently kept starved of all life by the Sentinels, of which more were produced by local manufacturing plants. The only signs of past life, besides the Flood, were dead trees and it was constantly snowing. It seems that the Sentinels or some other systems have caused this climate change in order to prevent life from growing and/or existing in this area, therefore denying the Flood of any possible sources of energy. It is unlikely that the change in climate was enacted by 2401 Penitent Tangent as the Monitor had not sent the requested "security detail" after approximately 287 years since the initial request for one. Likewise, the presence of trees at all indicates that it was not always such a cold climate, and is instead a response to the Flood outbreak.

History
Upon arrival within the Quarantine Zone, Covenant forces stumbled upon a four-way fight between the Flood, Sentinels, and the recently arrived United Nations Space Command forces. After the Arbiter had lowered the shield, more and more Flood had begun to spread into other sections of the Sentinel Wall and would conquer vast territories on the ring.

As Covenant and UNSC forces deployed mechanized forces from their ships, the Flood were able to overwhelm their occupants, infect them, then operate these machines in order to turn them on their foes. Their forces would grow to accumulate Ghosts and Warthog reconnaissance vehicles, and even Scorpion and Wraith tanks. The Flood's access to highly-mobile, and heavily armed and protected vehicles greatly multiplied their combat effectiveness on Installation 05.

List of appearances

 * Halo 2
 * Halo: Broken Circle
 * Halo 2 Anniversary