The answer is: he does, even if everything is happening at the same time. Writing in the latest edition of Headlines, the journal of the Headteachers' Association of Scotland, Cassels reports that word was received of an HM Inspectors visit in June last year eight days after the school had moved back into its partially-rebuilt premises which had been demolished after a fire.
Conflagration of a different kind followed as he fired off a letter to Ken Corsar, which the director of education described as "somewhat intemperate". But Cassels was only doing his job, reflecting protests from the school boards and unions.
Professional as ever, however, the inspection went ahead and Cassels even found it in his heart to praise the HMI's own professionalism and sensitivity. There were gripes, of course, particularly since the inspectors seemed short on that very commodity - praise - during the actual inspection. "I was left with the impression that I did not know how to put in a drawing pin," was one exasperated reaction.
There was not, alas, much opportunity for an in-depth analysis of the HMI report. It was published on the day of a staff meeting when Glasgow's dire financial state was outlined to the school. As a result, five teachers were fingered for transfer - some of them highly commended by the inspectorate.
Cassels could be forgiven for an air of desperation. But he's probably too busy trying to find out where some of his pupils have gone (page 1). Give that man a rise.