There is a rush of shuffling papers and the sounds of several desktops banging down. With five minutes left, desks bang. The class is ready to go. The professor does an experiment as a thin veil of noise covers the lecture. The classic zipping of schoolbags is heard throughout the room.
Many students get their pens going again.
At the end of class, the professor is still explaining, and the class doesn't succeed in leaving the room before the lecture is complete. Upon a few words suggesting dismissal, the class files out from the room. It's the last five minutes and it's a battle between teacher and students. Two wills clash, one trying to keep control, the other resisting. The last five minutes of a large class can be a very tense time.