I've seen the other raws of the manga, and they indeed had slept together fully naked inside the tent. Daren entered to deliver a report and apologized with embarrassment.
Funny, from what I remember in the webnovel, the receptionist was not really directly fired like in the manga, but only demoted in a much lower position, which is still practically the same as getting fired.
Because they have no idea that he was an SSS-ranked individual named Zero, they only know the codename but not his real name or even his face. Not even in the news was his real name or face revealed when it was announced that he was retiring.
Remember in the previous chapter, the NTR guy was...