"The course is full, so I need you to sign this form so I can enroll," said the student at the end of class. He was showing up to class for the first time a week or two into the quarter, after the first quiz.
"I can't do that. The Math Department office knows when people have dropped the class, and they can enroll you when there's an opening. You need to talk to them." If the course was full, that meant that the number of students was the same as the number of seats. I had learned in past years that if both the Math Department office and I signed students in, that caused havoc.
The student got very angry. He shouted at me and threatened me. He seemed unhinged, and I was afraid of what he might do to me. I hoped he didn't have a gun.
I thought to myself, "alienating the person who will give you a grade (if you're lucky enough to get into the course) isn't very wise." But then again, if I felt sufficiently cowed, perhaps his strategy was sound.
He demanded to know my name. My name was on the course list that he must have looked at to find out where my class met. If he wasn't smart enough to figure out my name, I wasn't going to enlighten him. I told him I felt threatened and didn't feel comfortable giving him my name.
I left the room. He followed me. My name was on my office door, and I didn't want him to know my name or where to find me, so I didn't want to go to my office until I threw him off my tail.
I walked down a hallway and up a flight of stairs, as I plotted my route. Then I sped up, ran down a flight of stairs, quickly rounded a corner, and ducked into the women's room. If he had good critical thinking skills (which seemed doubtful), he might have figured out that the only place I could have disappeared to was the women's room. If he dared to enter, I'd be trapped.
I locked myself in a stall, and waited for 15 minutes. I hoped that was long enough. When I left, he was nowhere in sight. From there, I took a circuitous route to my office, just to be sure that I'd lost him.
It would have been easy for him to have found out my name and and office number. I avoided my office for the next few weeks, and I never saw him again.
This took place at Ohio State. Something similar happened to me when I taught (while a grad student) at Princeton. I've heard similar stories from colleagues at UC Irvine. We aren't trained to deal with angry students, and our universities don't seem to have good ways to help us.