Security Team 3 was a Covenant security force stationed in the UNSC Pillar of Autumn's command and control decks during the Covenant's occupation of the downed cruiser. They were presumably all killed by John-117 as he made his way to the ship's bridge and then moved on to the engineering levels of the ship. Any who might have survived it were more likely than not killed by the detonation of the Pillar of Autumn's fusion reactors.