Using tech the Covenant acquired from Requiem, Dr. Halsey laid a trap for the UNSC which ultimately gave the Covenant both halves of the Janus key. After various experiments, Dr. Halsey pinpointed the location of the Absolute Record, not before the UNSC got wind of this and hid a covert strike force onboard one of Jul's ships. At the absolute record, the custodian - a Contender-class ancilla - brought all the humans to a platform. The Contender, confused as to why humans felt the need to hide, gave each side a test to see who was the true person to access the Absolute Record. During the test, Halsey subverted the Contender and disabled him, and accessed the record without its consent. With the help of the other humans (Palmer, Tanaka, Glassman), the Contender regained control and informed Halsey that she would have passed the test had she not cheated. Consequently, the Contender destroyed the Janus Key.