Once a capable biologist working at the Safari Adventure Replication Facility established by John-Caleb Bradberton, McDermot was the only survivor left at the facility after the devastation of the Great War. Left ghoulified by the radioactive fallout, he sustained himself using the Nuka-Gen Replicator to clone animals and slaughter them for food. Using his new state as a ghoul, the good doctor continued his research into cloning, only wishing for his colleague, Doctor Hein, to be present to guide him.
The research kept him sane for decades, if not centuries. The irony of using the Nuka-Gen to sustain himself was not lost on him. He was, after all, the facility's top geneticist responsible for cloning animals for entertainment. The machine continued to put food on his table, just in a more literal sense after the nuclear holocaust. His life took a turn for the worse when he spotted a group of scavengers wander into Safari Adventure. Knowing that that the Nuka-Gen Replicator couldn't fall into the wrong hands, McDermot became determined to create a specimen that could protect him, as well as the facility. Even after admitting that he was going against his better judgement, he spliced a few of the more dangerous tissue samples he had left in the refrigeration storage at the facility.
After a few years filled with mathematical and chemical research, he finally created something that could protect the Nuka-Gen Replicator: The gatorclaw. Unfortunately, they could not be tamed as Dr. McDermot had hoped. They were too ferocious, impossible to control. Worse yet, Dermot was injured by the gatorclaws before he could shut the replicator down, leaving it intact and creating new gatorclaws at "an alarming rate." McDermot died of his wounds and recorded a final message pleading anybody to access the cloning lab and deactivate the replicator before it was too late.
While they weren't exactly on time, the Sole Survivor hunted down the dozens of gatorclaws lurking around Safari Adventure in 2287, making the park inhabitable once more.