By saving Freddie’s life, and uncovering the conspiracy surrounding the Sylvan family, Nick consigned himself to incarceration anyway. His tactics were illegal, and Reminiscence would have ended with him in a jail cell. It just so happened he chose a different life sentence, and carried it out himself.
Ultimately, much like the story of Orpheus and Euridyce that plays a crucial part in Reminiscence’s romance, Nick eventually follows Mae back to the metaphorical underworld. While she’s physically dead, Mr. Bannister is functionally dead, never to set foot outside of his reminiscence tank ever again. The lovers are reunited, and the story never ends, which makes Reminiscence a potentially potent double feature with Inception; another story obsessed with Greek mythology and the power of memory.
Source: Cinema Blend