so what did they do to make it hilarious?

well, for starters, we were told that the kids will take a dump on their test before they start.

the bigger and nastier, the better (mind dump of fact-recall; test strategy)

then we were told the Supt (who will be joining us) is not allowed to be left in a room with children

(naturally that got taken out of context, since they meant 'alone with tests since he wasn't trained in test security')