Why does the following citation describe the theme, coming of age?

"We're all dead anyway. I should make a shish kebab of your kids."

I didn't mean it. I looked at their round eyes, wet and watching but not nervous enough for the threat of a human. Their dad was there, after all, and they knew they were safe. I felt tears collecting behind my own eyes like sand in a windstorm. I opened my mouth...to say what? To apologize to a group of wild guinea pigs? To explain that I hadn't meant what I'd said? To let them know I just missed my family?

p.8