Answer and Explanation:
First, we can say the tone of the excerpt is sad and regretful.
The author is careful in his word choice, especially when it comes to describing the man he killed. He does not describe him as an enemy, as dangerous. He does not try to convince himself or the reader that his actions were justifiable. The fact that he concisely explains how the killing happened, with direct sentences, also show he is being honest and straightforward. He does not try to paint a different picture of what happened. It is worth noting that he does not worry much about the man's appearance. All he says is that he was short, slender, and about twenty. We do not know if the man looked threatening. All we know is that the author was afraid, and that that was enough to do what he did.
As for the parts about his daughter and his own feelings, the author is also direct, concise. However, when he describes the man in his imagination, he gives more details, painting a more vivid picture than he did when he described the killing. Now we know how the man walks, what his posture and attitude are like. It seems that the author wishes to convey how his thoughts linger, how his regrets come back again and again.
