"Now there came a little 'flutey' bit--very pretty!--a little chain of bright drops. She was sure it would be repeated. It was; she lifted her head and smiled."
It allows the reader to see the action from the perspective of Miss Brill and to see her objectively.
It provides an opportunity for the main character to indulge in imagination.
Miss Brill views social interaction as a stage play.
Reliable sources are written by experts or credible reporters. They often list their own sources and are published on websites that are associated reputable organizations.