When Moishe escapes, he is able to bring back the news of what is happening in the camps. He has experienced the horrors of the Holocaust and wants people to be aware of what these mean. However, the Jewish people in the towns seem reluctant to believe him. Moishe's words are too intense and unimaginable for them to be reality.
Wiesel reports this information in a very matter-of-fact way because he has gotten used to the idea of it, and to the implications that come from this information. Moreover, he wants to emphasize the fact that this was the reality during this time period.