URBANA, Ill. — It was 10 p.m., and we were locked in a room at the mall.

It had been a long day. I had woken up at 5 that morning to finish writing an article. Then I had spent a day talking to University of Illinois students and professors. The physics department had invited me and two other science writers to visit, part of an effort to help science and engineering students better explain what they do.

I had had a few glasses of wine at dinner.

And now here I was in a locked room at Lincoln Square Mall, straining to recall my ancient physics education in order to get out .

The four of us — me plus Phillip Schewe, a longtime science writer; David Ehrenstein, an editor at the American Physical Society; and Karin Dahmen, a physics professor at the University of Illinois at Urbana-Champaign — had an hour to figure out everything about a missing scientist.