Looking after a group of students and making sure they don't do anything stupid is much more tiring than you'd expect it to be. There's a lot to do.
Still, it won't be long till term starts and I'm sure you'd all rather be with your friends at the castle than all packed in here at any rate.
Would you mind covering for me for a bit? I know I only have an hour till the end of my shift up here in the rooms' corridors but I'm so tired I could fall asleep standing up!