And he had made answer that he had as yet no definite information, but was inclined to suspect that when the Prioress had bidden the old woman begone, she had slipped into some place of concealment from whence she had seen and heard something of what passed in the cell.
To this the Knight had made no comment; and now, walking up and down the lawn, the white stone in his hand, the Bishop could not feel sure how far Hugh had taken in the exact purport of the words; yet well he knew that sentences which pass almost unnoticed when heard with a mind preoccupied, are apt to return later on, with full significance, should anything occur upon which they shed a light.
This then was the complication which had brought the Bishop out to pace the lawn, recalling each step in the conversation, there where it had taken place.
Sooner or later, Mora will tell her husband of Mary Antony's wondrous vision.

If she reaches the conclusion, uninterrupted, all will be well.

The Knight will realise the importance of concealing the fact of the old lay-sister's knowledge--by non-miraculous means--of his presence in the cell, and his suit to the Prioress.

But should she preface her recital by remarking that none in the Community had knowledge of his visit, the Knight will probably at once say: "Nay, there you are mistaken! I have it from the Bishop that the old lay-sister, Mary Antony, knew of it, having stayed hidden where she saw and heard much that passed; yet being very faithful, and more than common shrewd, could--so said the Bishop--be most completely trusted." Whereupon irreparable harm would be done; for, at once, Mora would realise that she had been deceived; and her peace of mind and calm of conscience would be disturbed, if not completely overthrown.
One thing seemed clear to the Bishop.
Hugh must be warned.

Probably no harm had as yet been done.