What causes madame schachters terrible visions

Answer

Madame Schachter's terrible visions are caused by her extreme fear and desperation.

Q: Who is Madame Schachter? A: Madame Schachter is one of the Jewish prisoners on the train heading to a concentration camp in the book Night by Elie Wiesel.
Q: What causes her terrible visions? A: Madame Schachter's terrible visions are caused by her extreme fear and desperation in the face of their situation. She becomes convinced that she can see flames in the distance and believes that they are heading towards a furnace to be burned alive.