'Hmm' thought Jake, he thought he had died, no he was positive that he had died. There should be no posible way to survive the chemical agent he exposed himself to, but the mere act of him contemplating this means that he is some how alive, or something similar to that position.
He was tempted to keep contemplating this but all of a sudden he felt an emense pressure, it constricted him from every angle. The more he tried to resist the more it tried to crush him, so he decided to take a chance and let it in. This was a mistake, as it quickly tried to pull away his memories, Jake, not fully aware of why or how it was doing this, was rather pissed, and forcebly dreged said memory back. 'this was my life's work, the culmination of my experience, and you want to take them from me? let's see how will be the first to crumble'.
Jake's struggles continued over and over and over, every time that strange energy tried to take one of his memories, he would drag it back. This lasted for minutes, then hours, then days, then weeks, all the while Jake is forced to relive his life over and over. The loss of his parents, his isolation in highschool, and his years in college, all of this comes back to him, weeks turn to months, months to years. He has at this point remembered all of his life, there is no detail that he doesn't remember, years to decades, decades to centuries. Jake has completely lost his sense of time, but the constant introspection causes him to keep his sanity, he also starts to piece together the strange energy. He learns how it works and how seeks out his memories. Jake slowly finds out ways to keep his memories hidden from it, it's a slow process, but eventually he succeeds in hiding away all that makes him him. After this, the energy stops probing him and his conscience fades to black. His final thought was that of how much of himself did he successfully preserve.