@Malte: That's because they're having an extra-marital affair. That thing stains a school reputation, which means everything. And they weren't fired, they "resigned" *wink, wink*, that's important. Reputation and honor, both communal and personal are REALLY important in Japan.
But I agree on that, that was a really dickish move. If he wanted to show his filming skills he should have done it in a better way.