This is a very interesting question. It seems as if the story presents the children in oposition to adults. When Tom gets angry because he is accused of not playing with Jenny by the Nurse, he lets the emotion completely rule him and responds as a child would, by throwing a tantrum:
Tom ran at the door and kicked it, rushed at the engine, picked it up and flung it against the wall. Then he howled at the top of his voice for five minutes. He intended to howl all day. He was suffering from a large and complicated grievance.
What is so interesting about this is that Tom seems to be completely uninhibited in his response. However, because of this uninhibited reaction, it appears that he is able to quickly put this behind him when Jenny returns to the room. The story seems to suggest that children have a somewhat healthier attitude to their emotions than adults, and that this allows them to express what they are really feeling, rather than bottle it up. This is shown when the peace and calm of the previous scene is restored once again so swiftly with both children engaged in their previous activities.