The principal of St Columb's College in Derry reflected on how things could have been very different after a lorry with a suspected bomb on board was abandoned outside his school.
"Imagine if we had had 1,500 boys in here and had to evacuate all of them. That would have been much more serious," said Finbar Madden.
"We were having a management meeting in the school with about 20 senior teachers and staff. On top of that we were preparing to dispatch the GCSE results and we had a lot of workmen getting the school ready for the new term.
"The first we knew of the alert was when one the secretaries left the school and could not get back.
"Then we got a call from the police to say we had to evacuate, which we did, out the back."
The school head added: "Luckily, with the co-operation of the girls' grammar school, Thornhill College, we were able to dispatch all the results so the boys should have them in the morning."
The alert resulted in a security shutdown in the surrounding area. Residents of a nearby development who had not been evacuated caused some minor headaches for police when some of them tried to see what was happening before being quickly told to go back to their homes.
At a nearby bridal shop the owner told of the anguish of a bride from Donegal who is getting married on Friday and was unable collect her dress.
Barry McGuigan, the manager of a nearby Lidl store, said he had had to turn back deliveries of fresh goods.
Derry mayor Brenda Stevenson condemned the incident. "The alert today has caused widespread chaos across the city," she said.
"Derry has moved on from violence, and senseless actions such as this inevitably have a wider impact on local business. I would call upon those responsible to listen to the people of this city and desist from inflicting further hurt and pain on their own community."