What happened the day that prisoners were hiding in the barracks from the air-raid signal? What was the temptation that all of the prisoners wanted?

In chapter four, Elie describes a Sunday when the sirens go off around ten o'clock warning the camp of an impending air raid. The SS officers seek shelter and the prisoners gather unattended in their respective blocks. While the prisoners are gathered together in their blocks, they stare at two full cauldrons of soup that have been left unattended by the kitchen. Elie mentions that hundreds of eyes were attracted to the cauldrons as the prisoners were tempted with the rare opportunity to have their fill of soup and an extra ration of food. Suddenly, a prisoner from Block 37 opens a door and begins to crawl towards the cauldrons of soup. Elie and the others watch as the prisoner crawls up to the cauldron and finally pulls himself to the rim before he is suddenly shot dead by one of the SS officers. This tragic scene depicts the lengths that the Jewish prisoners were willing to go to have an extra meal in the horrific concentration camps.

In Section 4 of Night there's an Allied air raid on Buna. According to standard procedure all prisoners are to be confined to their barracks. The last thing that the camp authorities want is for the prisoners to take advantage of the situation and try to escape. But because the prisoners are suddenly confined to barracks it means that two cauldrons of soup are left unattended. Everyone in the barracks is absolutely famished; they're deliberately given insufficient food to eat by the Germans and so they're always hungry. The cauldrons of soup, then, present a huge temptation to the prisoners. But with huge temptation comes huge risk. If the prisoners are caught eating the soup, then it'll be the last thing they ever eat. Driven on by insatiable hunger, one prisoner tries his luck and makes his way over to the soup cauldrons. As he stands over one of them, about to eat the soup, he's shot dead.