2nd.

Once on the train things started getting terrifying immediately. The people giving way openly to instinct is the first sign  that they could feel how bad things were going to get, also the fact that they knew to save their food. Im sure that there were other instances similar to the incident with Madame Schachter  on other trains and would be surprised if their weren't. The foreshadowing of her shouting about fire is spooky once you learn that it actually happened and wasn't something that Elie had placed into the story for a dramatic effect.