In Night, Chapter 6, what keeps Eliezer going during the brutal march?

Part of what keeps Eliezer moving onwards and not stopping is the presence of his father along side him.  The penalty for stopping is to be shot, so motivation of self interest is present. However, Eliezer seeks to maintain the bond with his father, despite the looming threat of death.  Eliezer saw instances where sons betray fathers, and Eliezer vows not to let this happen to him in his relationship with his father.  On the night march, he saw the Rabbi's son break away from his father in the belief that his father wound not continue.  Such a condition illuminates that the struggle for survival is one that pits son against father, breaking all hopes of bonds and unity.  Eilezer offers a thought, almost like a prayer, that he does not do the same to his father.  Eliezer's belief is that if he keeps going, so will his father, who is running along side him.  This notion of loyalty is something that is pervasive in this section and serves to motivate Eliezer into continuing to struggle to live and acknowledging the bonds of loyalty at the same time.