Mitena Haro appeared to be a Bolian Starfleet cadet held prisoner with Picard but was really one of the aliens running the experiment.
Mitena Haro presented herself as a Starfleet Academy cadet from Bolarus IX when she was found in the cell with Picard in Allegiance. She deferred to Picard as a fellow Starfleet officer and helped him try to break out alongside Esoqq and Kova Tholl.
Picard noticed that she knew information no cadet would have had access to. He confronted her, and she was revealed as one of the aliens studying the prisoners' responses to authority. Her people's experiment ended, and they returned Picard to the Enterprise, where his duplicate had been acting strangely. Joycelyn O'Brien played her.