Also I laughed so hard when the person was like "that person will have to disappear" because it just didn't seem plausible that they would track all of their former workers and just "eliminate" people who knew about the identity of the former worker. Like, what if they announced it on Twitter or something? Does that even count? Lol. js.
The only thing that makes sense to me is if the brothel's associated with/run by Yakuza; if it gets out that she's connected to the club, then she could be used to link the higher-ups to it. I don't mind it not being spelled out for a one-shot, but if Isya does continue it, it's definitely an area that needs to be explored.