Sondra Yei was the head of Cay Habitat's psychology and training department. Her duty was to perform "behavior shaping" upon the quaddies – which served both safety purposes and more political ones as well. At first, she publicly supported Bruce Van Atta's policies, however much she privately disagreed with them. However, by the end of the story she decided to adjust his "attitude" with a spanner to prevent him killing the quaddies.