Vader glowered. This time, it was definitely a test.

“I believe they are hibernation tanks,” he said. “Perhaps similar to carbonate freezing. The occupants were brought to Batuu, then put inside the tanks for secret transport across Black Spire to the Darshi houses. It was their sudden fear at the knowledge of what was to happen to them that the Emperor detected as a disturbance in the Force.” He paused, stretching out to the Force. “But you already knew they were Force-sensitive, did you not?”