During the Covenant invasion of Fumirole, a CCS-class Battlecruiser was holding position over a city. Lieutenant Commander Catherine-B320 of Noble Team came up with an operation to assault and destroy the ship with a Medium Fusion Destructive Device. Supported by the rest of Noble Team, UNSC Army infantry and air support by UH-144 Falcons, she undertook the task of delivering the nuclear device into the ship herself. However, she was wounded by a Banshee's Fuel Rod Cannon blast while on her way to the cruiser. The blast also severely damaged her right arm, which was later replaced by a robotic prosthetic.
Thom-A293 was the first to arrive to her position. Seeing as there would be no time to wait for backup, he picked up the nuke and used a jetpack to fly into the cruiser through its gravity lift. Just before the nuke's countdown ran out, Thom managed to toss it into a hangar bay where numerous Unggoy were massing for deployment. Mere seconds later, the MFDD went off, destroying the cruiser and killing Thom.
While the outcome of the larger battle is unknown, Noble Team was successful in destroying its target. However, Catherine-B320 and Carter-A259 both carried extraordinary guilt over Thom-A293's death, blaming themselves for the incident, despite the SPARTAN's own decision of self-sacrifice. Thom would later be replaced by SPARTAN-B312.