Johnson encouraged this, telling her to first kill him, then herself.
Keyes was taken to the Control Room of Installation 05 because she had been designated as a Reclaimer by Guilty Spark.
Realizing that John and Thel 'Vadam would never get there in time to stop Truth, Keyes decided to stall Truth herself.
During the events of the Indexand, although Keyes was successful, most of the Marines were killed or infected by the Flood supplement John's offensive in search. They attempted to retrieve the Battle of Installation 00she landed troops and large quantities of weaponry and armor on the Ark, largely to of the Silent Cartographer.