By putting it as a matter-of-fact statement (assuming everything else was action packed) there is a massive shift that creates contrast in the piece and leaves a very concise point to shock/leave the reader with.
It changes the tone in a more deep and meaningful way.
Explanation:
It contrasts because earlier, the text is enlighten, positive, empowering because the community is fighting for what they want, and they are showing ways on how they are united. Furthermore, when she ends it off with such a short sentence, it gives more meaning, It gives the tone of unexpected and deep. Its giving the meaning that most of them were fighting for their city back and died in the process. It seems as though with her writing style, the shorter the sentences the more meaning and power it holds. This is a clear example.