In chapter 5, Elie finds himself hospitalized because of extreme foot pain. He is worried that his foot will be amputated, rendering him "useless" in the eyes of Nazi officers and making him a primary target for the next selection. As he is recovering, he learns that the Red Army is advancing and is now only hours away from their camp. A doctor tells Elie that the camp will be evacuated the next day and that the sick can remain in the hospital.

This news strikes Elie as odd. Why would the SS leave the sick behind, possibly to be liberated after all the pain the SS had inflicted upon them? Elie's hospital neighbor is certain that all those left behind will be thrown into the furnaces. Elie thinks of his father, who is not hospitalized, and can't stand the thought of being separated from him.

Elie runs outside and locates his father; they discuss their options and decide to be evacuated with the others. Elie isn't sure that he can walk on his foot yet, but they commit themselves to the effort and to further imprisonment, believing that they stand a better chance at survival in choosing to go to the next camp.

After the war, Elie learns that those who remained at the hospital, where his father could have been admitted as a temporary patient as well, were simply liberated by the Russians two days after the camp was evacuated.

By the time of chapter 5 of Night, the Germans are rapidly losing the War, with the Russians making territorial gains in Eastern Europe. With the arrival of the Red Army being only a matter of time, the Germans make the decision to evacuate Auschwitz.

This news is bitter-sweet for Elie. On the one hand, the imminent arrival of the Russians gives him hope. On the other hand, however, as a convalescent in the camp infirmary, he's worried that the Germans will kill him and all the other patients before leaving. Elie knows what the Nazis are capable of; they wouldn't hesitate to kill the sick and the wounded, especially if it will hasten their evacuation plans.

So Elie figures that he has no choice but to drag himself out of bed and join the vast exodus from the camp. He believes that this is his only chance of survival. Even though he hasn't fully recovered from surgery on his leg, he still has to move somehow.

As it turns out, however, Elie was mistaken in believing that the Nazis would murder all the patients in the camp hospital. Years after the war, he finds out that the patients were left behind in the camp, where they were subsequently liberated by the Russians.

Eliezer’s foot started to swell due to the cold, making it impossible for him to move around. The situation forced him into the infirmary, and he was attended to by a Jewish doctor. The doctor settled on performing an operation on Eliezer in order to save his leg from amputation. The surgery went well, and Eliezer was set to recover. However, rumors spread around the camp that the front was drawing closer to the camp. The Red Army was swiftly making its way to the Buna concentration camp. The Germans decided to evacuate the camp and the prisoners prepared for the journey. Eliezer left the infirmary to find his father. He hoped that his father would make the decision on whether they should embark on the journey or stay in the infirmary. Eliezer suggested they be evacuated with the other prisoners and his father agreed. After the war, Eliezer learned that those who remained at the camp were liberated by the Russians.

"Well, Father, what do we do?"

He was silent.

"Let's be evacuated with the others," I said.

He didn't answer. He was looking at my foot.

"You think you'll be able to walk?"

"Yes, I think so."

"Let's hope we won't regret it, Eliezer."

AFTER THE WAR, I learned the fate of those who had remained at the infirmary. They were, quite simply, liberated by the Russians, two days after the evacuation.

In Chapter 5, the camp was to be evacuated because the Russians were approaching.  Those who stayed behind in the hospital "were quite simply liberated by the Russians two days after the evacuation".

Elie had actually been in the hospital recuperating from surgery on his foot when a rumor went around the camp that "the front had suddenly drawn nearer...the Red ARmy...was advancing on Buna, it was only a matter of hours now".  In the chaos that ensued, Elie ran outside to look for his father.  When he found him, the two of them weighed whether their chances of survival would be greater if they stayed at the hospital or if they ran with the others.  After some deliberation, Elie decides that they would be better off being evacuated with the rest of the prisoners.  It seemed unthinkable that the patients at the hospitals would be left unmolested to await their liberators; rumor had it that "all the invalids "would be summarily killed...and sent to the crematory in a final batch".

Elie learned later that had he and his father stayed behind at the hospital, they would have been liberated when the Russians came.  As it is, the two are forced on a grueling march to another camp at Gleiwitz, and then on to Buchenwald (Chapter 5).