Ms. Fennelly, the former poet laureate of Mississippi, teaches at the University of Mississippi:

Last year, one of my students turned 21, and her friends tied two giant Mylar balloons, a “2” and a “1,” to her chair to celebrate. Later, deep in our discussion of John Donne, we heard what sounded like a gun shot. Everyone jumped. A few screamed. One student — I can see him still — hit the floor.

When we realized, all of us, that our active shooter was none other than an exploding Mylar “2,” there was a painful pause. Then we laughed a shaky laugh, and I slowly resumed the discussion.

I wish I hadn’t. I wish I’d given them the rest of class to share how difficult it is to learn when one is always listening for a bullet.