A few minutes more, and words begin to drop, one by one, from those parted lips--words spoken in a lost, vacant tone, as if she is talking in her sleep.
Mrs.Crayford looks back at the house.

Sad experience makes her suspicious of the servants' curiosity.

Sad experience has long since warned her that the servants are not to be trusted within hearing of the wild words which Clara speaks in the trance.

Has any one of them ventured into the garden?
No.

They are out of hearing at the window, waiting for the signal which tells them that their help is needed.
Turning toward Clara once more, Mrs.Crayford hears the vacantly uttered words, falling faster and faster from her lips, "Frank! Frank! Frank! Don't drop behind--don't trust Richard Wardour.
While you can stand, keep with the other men, Frank!" (The farewell warning of Crayford in the solitudes of the Frozen Deep, repeated by Clara in the garden of her English home!) A moment of silence follows; and, in that moment, the vision has changed.