@DANDAN_THE_DANDAN Eh I thought you're the one. Because in the chapter 3, it said Miyagi will observe MC life in the whole three months and cease her observation for last three days. You can read carefully chapter 3 back.
@DANDAN_THE_DANDAN A much belated response, but for you and anyone else who was confused on this point, Miyaki sold off her remaining lifespan, keeping only 3 days, to pay off the rest of her debt. This released her from her obligation and her position, so that for her last 3 days, she was just a normal person, free to do with her time as she chose.