This shows Mr Birling lack of civic mindedness and how emphasises on how selfish he is. There are also other instances on how selfish he is. For example, when he only cares for his knighthood and his reputation when news gets round of his family causing Eva to commit suicide. There is also no doubt that he is a unfeeling man when he shows no regret and remorse when he sacked Eva. Rather, he feels that he was not responsible for Eva Smith's death.
Mrs. Birling had almost a 100 percent mirror of Mr. Birling except that she flexes her muscles as head of the charity organization to refuse help to Eva Smith. She felt that it was impertinent of Eva to call herself Mrs Birling. Furthermore, she was a liar (as her children soon found out) as she had refused to acknowledge the photo of Eva and was adamant about not having met her. However after repeated questioning, she admitted that Eva had came to her for help before. She is also in the dark about Eric's drinking habit and realizes that Sheila is not as pure as Mrs. Birling thought she was ("ran away with only a torn blouse..." "Shelia!"). This goes to show that Mrs Birling does not understand her children well enough to reveal their characters.
Sheila had been thought to be a simple-minded girl and who was always excited. However after tonight, she became a changed person. She became the opposite of her parents