Christopher explains that his Mother and Father used to argue a lot due to the stress of looking after someone with Behavioral Problems. He explains that he has grown out of most of his Behavioral Problems and lists them. The list includes: 'Not liking being touched', 'Smashing things when I am angry or confused', 'Not eating good if different sorts of food are touching each other', 'Saying things that other people think are rude'. Mother and Father sometimes used to shout at Christopher - Mother saying 'You are going to drive me into an early grave.'
When Christopher gets home his Father is sitting at the table where he had laid the baked beans, broccoli and two slices of ham (which aren't touching) and he tells Christopher that he has recently had a call from Mrs Shears. Christopher tells his father that he thinks Mr Shears killed Wellington and his father slams his hand down and says 'I will not have that man's name mentioned in my house...That man is evil.' He asks Christopher to promise not to carry on with his investigation and Christopher promises.
Christopher explains that he would love to be an astronaut and that he would be very good at the job: He is intelligent, he understands how machines work, he likes being on his own in tiny spaces, he would be happy because there are no yellow or brown things in a spacecraft (and he doesn't like yellow or brown things), he would be able to talk to other people from Mission Control who wouldn't be like strangers, and he would be able to look out at the stars and know that there was nobody around him for hundreds of miles. Ideally, he'd love to take his rat Toby with him.
The next day at school Christopher tells Siobhan that his father has told him to stop 'detecting'. Therefore the book he was writing is finished. Siobhan tells him that he should be pleased that he has written a book at all but Christopher says it cannot be a proper book because he never found out who the murderer was. Siobhan tells Christopher that life is like that: there are lots of murders unsolved and lots of murderers who aren't caught. Christopher doesn't like this idea and he worries about bumping into the murderer at night. He then asks Siobhan why his father said that Mr Shears was evil and tells her that he thinks Mr Shears is a suspect. Siobhan cannot answer Christopher. The next two days, Christopher sees 4 yellow cars, making them Black Days. On the third day he travels to school with his eyes closed - because, after two Black Days in a row, he is 'allowed to do that.'
It is significant that Christopher wants to be an astronaut. He wants to work in a vehicle that takes him as far away from earth as humans can possibly go. This shows how fundamentally distanced he feels from the world and the way it works and shows the relationship he would prefer to have with it: as though it were a computer game.
For the reader, there is definitely something suspicious about the fact that Christopher’s father became so agitated about Mr Shears, and about the fact that Mrs Shears is no longer a friend of the family. We can see that there is clearly something that is being hidden from Christopher, but Christopher cannot read the very clues he puts before us - he relates what he sees, but he cannot parse the emotional vocabulary.
Most of the things that Christopher lists under his behavioral problems are problems with communicating. His parents want to touch him to communicate affection but he does not like to be touched, and when he cannot communicate effectively (as when 'angry or confused'), he 'smashes things' and he says things 'that other people think are rude'.