This is how Peranza ends:
She's getting her weekly Owl's Wisdom tapping, the one where you sit quietly in your bedroom and think about the Law and yourself. (Keltham thinks it takes place early in the morning; it actually takes place during the Long Night, in case anything goes wrong then.)
Keltham's theory was that stresses wouldn't accumulate for too long, that way; wouldn't build up in a backlog that causes cascades and massive personality shifts all at once.
...it's a theory that doesn't really work if the person has spent her previous Wisdom minutes on reviewing Law notes, in a frantic effort not to have her own mind come apart from thinking all the thoughts and seeing all the things that are easier not to think and see when not under Owl's Wisdom.
This policy is in no sense the result of a conscious plan. It's just that some past Peranza, who didn't want to be an outcast heretic even if somebody claimed she would survive that, nor wish to suffer horribly in Hell after that - no matter how totally infeasible that life goal was starting to look for her - conditioned herself with pain and horror against the possibility of thinking thoughts that Hell and Security wouldn't like. That past Peranza made flinchy the sense of maybe being about to see, because you have to stop yourself before you think the thought, if your mind is being read.
And Keltham went on lecturing, day after day, from Civilizational attitudes and techniques that were, if not designed to turn him into a Keeper, at least designed to exclude every possibility of any dath ilani ever turning into anything remotely like Peranza.