However, during the events of Fallout 4, Virgil is no longer affiliated with the Institute and has gone into hiding. His decision to break off from the Institute stems from his doubts regarding the group’s motivations, as well as the unethical nature of the FEV experiments.
The Institute began researching the FEV long before the start of Fallout 4, specifically in August of 2178. Note that this was long before Brian Virgil became the head of the research project. The Directorate had approved research on a number of samples of the virus, which the scientists had already gotten their hands on. Even though some of the other scientists were hesitant to push through with the research for fear that it may have been a dangerous undertaking, the Institute went on with their experiments.
The Institute of Fallout 4 supplied the FEV lab with a steady stream of “subjects” — likely kidnapped wastelanders. These unfortunate subjects were submerged in vats that would expose them to the FEV strain, and the scientists would then study how they reacted to the virus. Nearly all of the subjects followed the same pattern. At first, they’d exhibit physical and intellectual growth, but then these qualities would quickly devolve after some time. The subjects’ aggression would also worsen, turning them hostile to the Institute scientists. Because of this, they had to be disposed of.
Much later in 2224, the scientists in charge of FEV research reached an impasse. According to one of the scientists in charge, the subjects had been exposed to too much radiation and were unfit for testing. Thus, to further their research on the FEV and synthetic organics, the team would need less radiated subjects. This was likely when the Institute got the idea of kidnapping Shaun, leading up to the events of Fallout 4.
Aside from kidnapping Shaun, the Institute also conducted another FEV-related experiment in Fallout 4. This time, it was on Edgar Swann, a low-ranking Institute staff member before the year 2287. He had been caught stealing cigarettes and was then sentenced to “probation.” This required Swann to stay under the Institute’s care for a month. They’d supply him with the food and water he needed, and all he had to do was write in a journal every day. This was one of the experiments that Virgil presided over during his time in the Institute, and was likely one of the factors that contributed to his decision to leave.
After learning about Swann’s acts of theft, the scientists infected him with a strain of the FEV. On the sixth day of his probation, he reported feeling jittery. His bones were aching, and he could barely keep his mind in check. By the 14th day, his mental faculties spiked. In his journal, he writes about his physiological and mental evolution with surprising eloquence. Swann even asked to join the Institute’s research team in Fallout 4, believing that he may be able to assist the organization with his newfound intelligence.
Unfortunately, by the 21st day of probation, Swann realized that the FEV he had was highly unstable. His intellectual abilities had peaked but were quickly devolving as the days passed. He was also experiencing disruptive seizures. At this point, Swann was fearing for his safety. He had an inkling that the Institute might throw him out, like the rest of their failed experiments in Fallout. He was right.
Swann was exiled into the Commonwealth of Fallout 4, where he made his way to Boston Common. Taking refuge in the local park, he built a home in an abandoned shack in the area. Unfortunately, the FEV was taking a toll on his mental faculties as he had to write a note that simply said “YOU ARE SWANN” — likely to remind himself of his identity. Eventually, Swann succumbed to the virus, losing any sense of humanity in the process. By the year 2287, wastelanders know to avoid the Swan’s Pond as it’s home to a ferocious super mutant behemoth.
It’s experiments like that of Swann’s that led Virgil to question the legitimacy of the Institute’s FEV research program. To him, there was no point in continuing the tests as there have been no deviations to their results in the past 5 years. In the year 2287, he filed a formal complaint to the Directorate, likely to demand answers about what they stand to gain from the FEV experiments. Unsurprisingly, he got no answers from the higher-ups, even as he requested that the program be shut down.
Eventually, Virgil decided to take matters into his own hands. He was overwhelmed by the guilt that came from experimenting on unwilling subjects, so he sabotaged the whole lab. After this, the Institute cordoned off the lab as a biohazardous area. Virgil’s actions — which the Institute refers to as “Incident V” — effectively put an end to the FEV research program. Meanwhile, Virgil escaped to the Glowing Sea of Fallout 4, where he hoped the Institute wouldn’t find him.
At some point, Virgil morphed into a sentient super mutant. It’s unclear why the FEV seemed to have worked in his favor when it led to the other subjects’ demise. Regardless, Virgil was aware of the risks of his infection, so he requests that Fallout 4’s Sole Survivor acquire the experimental serum, which will allow him to turn back into a human. Doing so will lead to him becoming human again. However, failing to acquire the serum will end in Virgil requesting that the player kill him.
Overall, the Institute’s research into the FEV and Virgil’s subsequent decisions showcase the organization’s morally dubious nature. Although this wasn’t fully explored in Fallout 4, there are snatches of it in terminal entries and character stories like Virgil’s.
Fallout 4 is available on PC, PS4, and Xbox One.