A proper person would look at the chaos andthink of burglars, and telephone the police. It seemed per-fectly obvious, as obvious as one plus one equalling two.But it hadn’t been obvious yesterday, when I was filling myuncles’ kitchen sink with green cordial
Here we see that Sonya is self-aware about the problem. Part of the reason she is deflecting is because she doesn't just feel embarrassed about the mistake - she feels stupid, and childish. She doesn't want people to look at her as if she was a dumb stupid kid.