Flood Containment Facilities

Summary
A Flood Containment Facility is a facility that was once used by the Forerunners in order to research and study Flood specimens.

Installation 04
Installation 04 had a Flood Containment Facility located under a swamp. The Covenant, thinking that this Flood Containment Facility was a weapons cache, secured the facility, and were brutally attacked by the Flood. The Sangheili were all killed or infected, while a few Unggoy and Kig-yar remained. After the attack, the Covenant locked the door of the facility in hopes of containing the Flood.

However, after interrogating the Sangheili 'Qualomee, Fire Team Charlie made their way to the facility, under the impression it was a weapons cache. After unlocking the previously locked door into the facility, the Flood infected every member of Fire Team Charlie other than Avery Johnson. The Covenant forces were scattered, and the UNSC forces were desprately defending themselves against the Flood. After John-117 arrived at the facility, the only thing he found were Covenant corpses, a crazed marine, and a recording chip telling the story of the battle against the Flood.

After fighting his way back to the surface, Master Chief managed to regroup with Corporal Lovik's Second Squad. However, 343 Guilty Spark abducted Master Chief, stating that he was a Reclaimer, and sent him to the Library to obtain the Index. Later, Master Chief managed to destroy Installation 04 after detonating the Piller of Autumn's reactor cores.

Threshold
While on the Gas Mine, the Arbiter Thel 'Vadamee had come across a containment facility. This explained the presence of Sentinels, who were under control by 343 Guilty Spark. The Flood that were here were most likely killed after the Battle of the Gas Mine.