Answering a question with a command will usually sound dismissive—one character is purposefully avoiding giving the other the information they want. Exactly how that comes across depends on the relationship between the characters and the context of the situation.
In the original snippet, Auggie's dad is avoiding having a difficult conversation with Auggie. He tries to use his authority as a parent to get Auggie to leave ("Go back to sleep, Auggie").
While his intentions are well-meaning—he wants to avoid causing Auggie more anxiety—we get the sense that he is dismissing Auggie's current emotions (i.e. Auggie is already anxious, and his dad isn't addressing that).
The first worked example is a bit different because of the context (being in a dangerous situation). The narrator isn't being dismissive of Cali—rather, by calling for immediate action, they are signalling that there isn't time to answer the question. (But notice that the result—avoiding a conversation—is the same. It's the motivation that has changed.)
Try describing the second worked example by yourself (or discuss it in a group).
- What is the "commanding" character trying to achieve?
- What does this say about the relationship between the two characters in the snippet?