With suddenly enlarged pupils and a movement as instinctive almost as the bounding of a startled fawn, she jumped up and found herself in the middle of the big room, exclaiming at those amazing and familiar strangers.
"What do you want ?" You will note that she cried: What do you want?
Not: What has happened?
She told Mrs.Fyne that she had received suddenly the feeling of being personally attacked.

And that must have been very terrifying.

The woman before her had been the wisdom, the authority, the protection of life, security embodied and visible and undisputed.
You may imagine then the force of the shock in the intuitive perception not merely of danger, for she did not know what was alarming her, but in the sense of the security being gone.

And not only security.

I don't know how to explain it clearly.