Lieutenant T'Ruveh of Vulcan was among the Starfleet officers taken captive by Cardassians in 2375 during the Dominion War. (Star Trek: Sigils and Unions)
For some period before the war, T'Ruveh served in a covert operations unit, evaluating potential worlds for Federation contact and membership.
When fellow prisoner Makis Spirodopoulos revealed that the Cardassians running the Lessek camp were in fact rebels against the Dominion, T'Ruveh was one of the first to advocate accepting a Cardassian offer to join the rebellion, stating she believed this the more survivable option than taking refuge in the mountains for the duration of the war.
Gul Rebek--though finding T'Ruveh's service background distasteful--would leverage the Vulcan's covert-ops skills during the battle for the Lessek shipyard, tapping her to fight in one of the Thirteenth Order's infiltration teams. Unfortunately, T'Ruveh died as the result of injuries sustained in the battle, despite the efforts of Cardassian doctor Midzour Hetalc to treat her. Her katra was transferred to Cadet Subek. (Star Trek: Sigils and Unions--The Thirteenth Order)