At some point after the Brood War, Garr attended a presentation by Dr Sandrew Loew on the notion of controlling zerg hydralisks through the use of a PPO. Garr was skeptical as to the worth of such a notion—if the PPO had to be inserted manually into individual zerg strains, the project wasn't viable in his eyes. That, and he was skeptical of the notion of controlling zerg, remembering the UED's failure with Project Black Flag. Loew demonstrated the control she possessed over her test subject, which resulted in marines being called into the demonstration theater. Loew showed how she maintained control, and Garr ordered the marines to stand down.
Garr met with Loew afterwards, where they discussed other elements of her project—control, failsafes, etc. Appreciating the idea, he gave Loew a minute's tele-conference with Emperor Arcturus Mengsk. Noting her apprehension, he reassured her that the emperor only punished failure. At the conference, he appraised Mengsk on Project Tamed, vouching for its feasibility for both internal and external applications. Loew gave him more information, and Mengsk gave the project approval, ordering Garr to focus on results. With that done, he gave Loew a timetable for human interaction trials, before turning to the matter of Thys, a Fringe World with anti-Dominion sentiment.
Three weeks later, Garr met Loew at the Tamed's testing ground, where he passed on commendations from Mengsk and other Dominion officials. With that done, he informed her that the Dominion intended to use the Tamed for a real-world situation—Thys, where a refinery under threat from feral zerg. Dominion forces were to be on the ground in 36 hours, and that included the Tamed, where the engagement would be observed by members of the Xenobiology Department of Special Research Ops, as well as their military counterparts. He assured her that it would be a mop-up operation, with only the possibility of sustained combat, said combat being against the malcontents within the refinery. Should the colonists turn on the Dominion, they would be the next target. Loew protested against the notion of using the Tamed against other terrans, but Garr brushed the complaints aside. The program's purpose, in his mind, was redirection of zerg to targets of Dominion choosing. And that potentially included traitors.
The operation was a success, as the Tamed operated in conjunction with Dominion forces, eradicating the feral zerg. Garr touched down on the ground, ordering her to have the Tamed move on the refinery. Loew realized that Garr had intended the Tamed to be used in such a manner from the outset, and had the hydralisks attack Garr and his accompanying staff instead. In terror, Garr reached for his sidearm, but a hydralisk cut him from shoulder to opposing hip, cleaving him in two.