That's precisely what a lot of things are: just one of those things.
These days there seem to be no accidents, mistakes or oddballs. Everything is a cause for litigation and endless investigation.
Sometimes crap just happens.
And in this case when crap happened, it was dealt with thanks to past experience.
How would *you* have stopped this incident? Demanded a psychiatric assessment of each deportee? Send a policeman with each deportee? At great expense to prevent a nonincident, whereby nothing happened because there was, thanks to past experience, very little more that could happen?
This was little more than someone having a paddy midair.