I think the case of mother Theresa is instructive here. Taught from an early age that salvation could only be found through devotion to her "christian duty" she worked all her life. But NONE of their upper clergy could EVER offer her any explanation for why it NEVER worked. Of course they couldn't. They know EVERYTHING about doctrine and ritual, and absolutely NOTHING about how spiritual purification actually works. All they ever knew to tell her was "keep at it and trust in God"

She never found a moments peace, and it seems that her growing frustration and heartache eventually found relief through the expression of sadism and ambition.

Just like the priesthood can be a magnet for confused young men trying to suppress, deny, or escape their true nature, maybe the Vows of the sister can be corrupted in the same way.