I've had a couple of people ask me about the 'teacherless classes' I've mentioned for next term. I've written mine in advance, in case I can't be on when it's needed, and will post it below so you can all get an idea. I've done it for DADA as that's the first class for Intermediates. Obviously, I was limited by not having a specific character for that - you could also discuss how characteristic it is (or isn't) for the Professor to be late, what the class would have been studying and whether there's anything in the room that might let them deduce that.
Selina
*
A strange stillness hung over the Defence Against the Dark Arts classroom on the first Monday morning of term. It was that peculiar atmosphere created by the arrival of the students preceding that of the teacher, and settling uneasily in, unsure how much noise would be tolerated upon their professor's arrival. It was very strange, for the Professors of Sonora were normally punctual to a tee. However, the professor for this class was new (a new professor had been introduced at the feast, had they not? Or was it going to be Professor Valson?) and perhaps that accounted for their tardiness. Another possibility that could never be ruled out with this subject was that some sort of surprise was going to be sprung upon on them to test their reflexes. The room gave no other clues as to the lesson for that day, and that would certainly make a strong first impression... There were possible reasons, definitely, for the absence of a teacher. Although the longer that elapsed, the less likely any of these really seemed.
The minutes ticked by, threatening to veer out of merely late and into rude or, worse still, the class having bee forgotten. How long any class would bear up under this was very much determined by the individuals. One thing, however, was certain and that was that the longer any such absence of a professor continued, the more likely it was that the delicate atmosphere would fracture and that dissent and disorder would spill out, anything from outbreaks of louder-than-usual chatter to declaring the class to be clearly over and leaving the room. Paper aeroplanes could very quickly become involved.
Whatever course the students chose, whether allowing their behaviour to slide or waiting dutifully for the lesson to begin, there came a point when even the most devoted academic or strictest observer of rules would probably have to concede that no-one seemed to be coming.