wiesel and his father have a choice what is it what do they choose why do you think they made that choice

Two days after his operation, Eliezer hears that the front is advancing to Buna, and that very day the camp is ordered evacuated. Hospital occupants will not be evacuated, however, and Eliezer worries that all invalids will be exterminated. He runs to meet his father outside, and his right foot leaves bloody marks in the snow. After some deliberation, Eliezer and his father decide to leave the hospital and be evacuated with the rest of the prisoners. Later Eliezer learns that the hospital occupants were liberated by the Russians two days after the evacuation.