Containment shield

The Containment Shield was a shield wall around Installation 05's Library made by the Forerunners. It helped contain and enclose the Flood inside the Quarantine Zone, and keep out anything that could sustain the Flood. It also appears to be a sort of energy field that doesn't allow anything through either way. In Halo 2, it was found guarding the Quarantine Zone, and keeping the UNSC forces stationed of Delta Halo (as well as the Arbiter) from reaching The Index. It had to be lowered and deactivated in order for the Arbiter to enter the Library and recover the index. In order the lower the Containment Field, the Arbiter fought his way through the Sentinel defenders and deactivated the generators for the shield. However, the generator couplings were protected by a Sentinel Enforcer. After destroying the Enforcer, the Arbiter finally deactivated the shield. This allowed access to the Quarantine Zone by the Covenant and the UNSC, giving the Flood hundreds of new hosts. The Flood was released onto the rest of Installation 05. As a result of this the UNSC In Amber Clad was taken over by the Flood and flown into the Covenant city of High Charity. It was observed during the level The Sacred Icon.