I had thought "Derailment." But what with the appalling habit our hero has developed of going his own way, the nature of his derailment might not be correctly summed by the word "Derailment." It's a problem that I could solve with the French word Detournement, which has an accent acute over the first e.
I know very well that English Speaking People are very suspicious of the
diacritic in written words. Use a cedilla and eyes start to roll. We prefer
incomprehensible spelling. So it's a problem, Fortunately there are alternatives
to "A Derailment." I just cannot think of them at the moment.