After the destruction of the Dylarian Shipyards, UED admiral Gerard DuGalle's next action was on Tarsonis. He believed the abandoned planet housed the Psi Disrupter, a potent piece of Confederate anti-zerg technology. It could disrupt zerg psionic communications, throwing them into disarray. He said that while Arcturus Mengsk had searched the planet for the technology and failed to locate it, the UED's scientists were able to do so.
Duran suggested the Psi Disrupter was such a powerful and dangerous piece of technology that it should be destroyed before Mengsk could get his hands on it, but Stukov believed its anti-zerg abilities would greatly assist the UED in defeating the zerg. DuGalle agreed with Duran. He ordered Duran to descend to the surface of Tarsonis to reach and destroy the Psi Disrupter.
Four zerg hive clusters stood in the way, but through careful attacks, Duran was able to destroy the Hives one by one. Doing so rendered the zerg docile, as Duran had suspected they would. Upon reaching the Psi Disrupter, he was surprised by ghosts working for Stukov. They said that Stukov would destroy it himself, so Duran withdrew.