Her mother might be very ill, might be dying, might be dead.

It was not for trifles that people sent such telegrams.

The astounding thing was that she should have been so blind to her obvious duty....

And she said to herself, thinking with a mysterious and beautiful remorse of the last minute of her talk with Mr.Cannon: "If I had done as I ought to have done, I should have been in London, or on my way to London, instead of in the room with him there; and _that_ would not have occurred!" But what 'that' was, she could not have explained.
Nevertheless, Mr.Cannon's phrase, "It's a good thing you didn't go to London," still gave her a pleasure, though the pleasure was dulled.
Then she tried to reassure herself.

Sarah Gailey was nervous and easily frightened.