it's a little sad. i wonder if its because its a shoujo. i know series like vinland saga are allowed to have that time, so its sad something like this has to be rushed.
i mean, he IS their boss, im sure if he had enough charisma a single "woah, we're going to an S&M club?!?!" probably would have stalled them. not to mention, he didnt continue his warning attempt to the place.
but i do agree miu gave mixed signals, maybe to set him up