Part of the reason that 'teacher' was so enraged was not only the sheer disrespect he perceived in her actions, but insult to his masculinity and position. He's a product of his upbringing, that has told him all his life that women are not only inferior to men, but that the only 'dutiful' woman is one that is seen and not heard, obeys without question, and yet works like a plowhorse behind the scenes to make a man's life easier. He feels that she's spitting on everything he 'knows' to be true....and it also would damage his reputation terribly, if word were to get out, that he could not control a slip of a girl in his own classroom. That he'd been hired by the palace; to be seen as having failed at that duty would be ruinous to a career.