From Halopedia, the Halo wiki
In October 2552, Kovalic was stationed on a remote UNSC outpost when it came under assault by Covenant forces. Kovalic was being extracted from the world's surface along with the base's AI when his evacuation Warthog was attacked. He was saved by Shock Trooper Sarah Palmer who managed to take down a Jiralhanae Chieftain and transport Kovalic to his extraction point. Palmer was later promoted due to her role in rescuing Admiral Kovalic and the AI he was guarding.
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