I don't think that I was thinking much when an eerie second of silence fell over Science Center B, about a half minute into the fourth slide of my Literature and Arts B-21, "Images of Alexander the Great" exam yesterday. I had been wrestling with the question of whether the manuscript being shown was Byzantine or Islamic, whether the title was "Alexander fighting the Persians" or "Iskandar versus Dara."

A moment earlier, I had looked up from my exam to hear frenzied shouting. A man in the front of the room had his fingers pointed like a gun and a book bag in his hand. The professor accosted the man, and the man shouted something back. He said he had a bomb, I think.

Then there was that second of silence, and I sat there. I think that most people in the room were coming to the realization that this man posed a serious threat. I, too, might have thought something about how this man was dangerous.

I never made a decision to run, either consciously or unconsciously. The man claiming to have a bomb was yelling at us to stay put, but somebody started running, so we all started running. I couldn't have made the decision to run, because even as an after-the-fact hypothetical--what would you do if a man with a bomb appeared in your classroom?--I can't make a decision.

Do I stay and risk a long hostage situation or take the risk and run? I've seen people run before--aerial shots of students pouring out of Columbine High School come to mind--but if the guy really has a bomb, is running the safest policy?

The noise of hundreds of padded seats flying up in unison broke the second of silence. I don't remember hearing any voices as we bounded up the stairs. I turned back and saw Professor Mitten still seated at the front of the classroom.

My first recollection of conscious thought came when I saw a girl stumble in front of me. Slow down, I said unassertively, but we were soon out of the auditorium anyway.

Once the door closed, separating me from the man with the bag, the danger he presented made no impression on me. I jogged for a second and even turned to a classmate next to me and cracked a smile.