Not set in stone...
Nice choice of words (Pompeii in mind...)
I suppose these early pioneers will have the engines borescoped pretty regularly - the 'airtests' of yesterday were only of a few hours duration. The cumulative effects of 20, 50, 100 hours flying will be the proof of the pudding.
The only slight concern is that all engines on each a/c will have operated in the same conditions, so if one were to suffer contam. the others would be in a similar state.
Here's hoping that all will be well.