Preston was present on Char in the battle that resulted in the de-infestation of Sarah Kerrigan. Entering the hive, she provided Kerrigan with a respirator and insulweave. She advised Jim Raynor that she was making guesses as to her physiology, that she was treating her as if she were human, to which Raynor angrily responded that she was human.
As the Raiders made their way across the surface, Preston took Kerrigan from Raynor's arms as they entered the Fanfare. Raynor requested that she be general and she obliged. Onboard the dropship, she advised Raynor that Kerrigan needed to be taken to the Hyperion due to its facilities. She still considered Kerrigan as a zerg, and refused to agree with her commander's assertion to the contrary. The dropship ended up docking with the Bucephalus, and with Rolfsen, Preston took her to have medical care.
Later, as the Raiders escaped Space Station Prometheus, Preston greeted Raynor again on the Fanfare. Annabelle Thatcher was killed due to an uncontrolled psionic attack from Kerrigan, and Preston told Raynor of the circumstances. The Raiders departed the space station.