They were assigned to defend the Vorknkx Project not long before the Battle of Endor. While they were stationed at the project's research center, treacherous Grand Admiral Demetrius Zaarin sent one of his Nebulon-B2 frigates, the Z-Borus, to capture the CR90 corvette Vorknkx, the project's testbed ship. It was carrying the latest Imperial cloaking device, which Zaarin was obsessed with having. Sentry group was responsible for laying down a minefield around the Vorknkx as a defensive measure when the traitors attacked. Their survival was vital to the defense of the Vorknkx Project, so pilot Maarek Stele was sent to defend these ships and the facility. Stele succeeds in destroying most of Zaarin's forces, including the Z-Borus, so Sentry group was able to lay their minefield and flee the area shortly afterward. The Vorknkx Project had remained out of Zaarin's hands for a while longer.