Which text from the short story “ambush” by tim o’brien exemplifies the theme of soldiers’ reticence, or inability, to discuss their experiences at war?

It was a difficult moment, but I did what seemed right, which was to say, "Of course not," and then to take her onto my lap and hold her for a while. I had come to a crouch. It was entirely automatic.
He cannot manage to speak about the war here, with his own daughter.