Answer:
The men reacted apathetic and did not show any emotion, as they were used to living with death beside them.
Step-by-step explanation:
From the context of your question, we can see that you are referring to the book "Night" written by Elie Wiesel. In this book, we are introduced to the terrors of the holocaust, as the book shows the moment when fourteen-year-old Elie Wiesel was taken to Nazi concentration camps with other Jews where they suffered terrible physical and psychological abuse.
When Elie Wiesel is being taken to the concentration camps in Buchenwald, he and the men with him observe the crematorium chimney where Jews were burned. They knew that this was a sign of imminent death, but they didn't show any emotion and reacted apathetic, since the Nazis made them used to live in constant threat of death.