You fell down. Your phone hit the pavement with the unmistakable clack of cheap plastic against asphalt. And then the rest of you followed.

I was shocked. Maybe not as much as you. Because you did something odd. You just picked up your phone, got up, ran around the wall and continued on. As though nothing had happened.

I yelled, “Are you O.K.?” but you didn’t glance backward. You just kept running.

I read it as a testament to the fear of social embarrassment over concern for your own welfare. That I can understand. But are you O.K.?

I think that because it was a temporary wooden wall, it would have yielded a little. It could have been a lot worse. You got lucky.

I was on my way to a talk by Rutger Bregman, an author who was visiting the university and who offers an optimistic view of the future. I had hoped maybe you were on your way there, too, but you weren’t.