Security Exception and a case of perfect timing

My students had their mid-semester test last night. It was a practical programming test, held in the computer labs from 6:30pm - 8:30pm.

I arrived at 6pm to set up. The lab was locked. This wasn't unusual. I have a key and swipecard and usually have to swipe myself in at that time. I swiped in and was immediately greeted by a cacophony of alarms. Now this was unusual.

I raced for the security phone, the siren resonating shrilly in my head, and waited impatiently for them to answer.

"I'M ABOUT TO HAVE A TEST IN OLD CHORAL HALL 1.25 AND ALL THE ALARMS ARE GOING OFF", I yelled over the din, "CAN YOU TURN THEM OFF?" A vaguely apologetic voice on the other end must have done something because the noise cut off abruptly.

"Thank you" I breathed a sigh of relief. Ok, great, so the noise was gone but the lab was still locked: I had to swipe all the students in myself.

It took about 10 minutes to set everything up, and then we let the students in. Most of them were fairly orderly, but I had to shift a couple who parked themselves at the wrong computers.

Once people settled down, I assumed my role as test adjudicator: "Okay, everyone", their eyes swiveled to me as I spoke in my best commanding lecturer voice, "it appears that we are locked in this lab. We can get in and out of that door by button and swipe card," I pointed down to the main door, "but we can't get in and out of the door behind me at all."

The moment I said it, all eyes fixed upon the door behind me as (in spite of my assertions) it miraculously opened. A bashful latecomer ducked into class and hurriedly took a seat.

Not for the first time, I cursed security under my breath.