Combat Team Baker
From Halopedia, the Halo wiki
"Baker" was stationed aboard the UNSC Pillar of Autumn in 2552. Following the ship's arrival at Installation 04 and the ensuing space battle, Fireteam Baker reported the presence of Covenant boarders on port deck 7. Cortana directed security teams to the area to assist in Baker. Eventually, Captain Jacob Keyes would initiate a general evacuation of the ship, ordering combat teams Alpha through November to evacuate. Combat Team Sierra through Combat Team Victor evacuated after them.
Combat Team Baker's fate upon Landing on Installation 04 is unknown, though it is likely that any survivors were part of the battalion led by Major Antonio Silva later in the conflict. By the time of the destruction of the ringworld three days later, Combat Team Baker (along with all other local UNSC and Covenant forces) was killed.
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