What is the foreshadowing for the quote "In front of us flames, In the air that smell of burning flesh" in Night?

This quote comes at the end of section two of Elie Wiesel's memoir Night. The Jews of Sighet have been transported by train from their homes to Birkenau, the reception center for the infamous Nazi concentration camp Auschwitz. As they arrive and step off the train they are greeted by the flames of the crematories and the smell of burning flesh. This scene is foreshadowed in the words of Madame Schächter who, from the beginning of the journey, has been screaming out that she sees fire and flames, but when the men look out the windows they see nothing:

"Look! Look at it! Fire! A terrible fire! Mercy! Oh, that fire!"

Some of the men pressed up against the bars. There was nothing there; only darkness.

Madame Schächter's cries leave the Jews uneasy as they try to convince themselves that she has simply gone crazy. They tie her up and gag her, but she breaks free and continues raving about the fire. Once they arrive at Birkenau, the flames come into view proving Madame Schäcter to be a prophetess. Once they disembark, Elie loses sight of Madame Schächter and her son. Like his mother and sisters, he never sees them again. Later, in section three, just as they turn away from the burning pit of flames they have been advancing to, Elie's father reminds him of Madame Schächter.