In this passage, Alice observes a humorous situation where everyone around her appears serious and grave, even though the scene seems absurd. She feels the ridiculousness of the moment but refrains from laughing because of the serious expressions on their faces.
Faced with the awkwardness, Alice chooses to remain solemn and respectful, simply bowing and accepting the item given to her, the thimble. Her reaction shows her attempt to maintain composure despite the absurdity surrounding her.