A last chance? If she had done the right thing and apologized or retracted it, she would have shown up at Mary's Room and observed absolutely nothing of interest or been ejected or confounded or something. The trope might be Last-Second Chance, although this seems to be more of a martial-arts sort of trope where you are ultra-polite and correct as you give the other person a clear statement of their mistake and a chance to rectify it before you open the can of whoop-ass on them (Martial Pacifist).