Possibly that hearing those bells isn t something one ought to hear after having done something as having trapped them in a crypt, but something less cheerful for such an act as his. Guilt.
The words are used to show quick, straight actions, they are scattered about so that the reader has the impression that the scene is impactful as the excerpt "I was struck by the intimacy scene." shows. There is also the idea that only the ones engaged in the conversations are allowed to hear their content and finally, these people are free from their masters -- teachers, parents and any other adult that symbolizes authority.
It implicitly states that Greta does not like her gift because she does not actually say it.