Why does madame schachter scream? why does she later become silent and withdrawn?

She is in the same train car as Eliezer, during their deportation to Auschwitz. She was separated from her husband and two older sons, but is accompanied by a younger son. During that journey she loses her mind. She begins to hysterically scream about a flaming furnace that she sees in the distance. This is terrifying the other people, so she is beaten by some younger men trying to silence her, repeatedly. I think all that made her become silent and withdrawn.