Pretend you're a law lecturer, your life will be immeasurably easier. Walk in, refuse to make eye contact with anyone, turn off any dictophones or other recording mechanisms that students have put near the lectern, slouch at the lectern in a way that students can only see the top of your head, start reading your lecture regardless of the noise or preparation of the students, refuse to accept questions then walk out after 30 minutes having speed-read through the entire thing.
At follow-up tutorials, you can then preside with a smug Professor Snape type attitude and berate any student who didn't instantly understand every word of your lecture.
Ahhh, the heady days of being a law student... how I miss them.