How did Chaya's prior knowledge of the future lead her to understand the danger that awaited the group at the shul

The Devil's Arithmetic conveys important understandings about what was endured during the Holocaust, and it is able to do so through two very different settings; modern-day New York and 1942 Poland. The main character, Hannah, is a young Jewish girl living in New York. While she has been well-educated on the atrocities of the Holocaust through school and through her family's personal struggles during the time, Hannah is bored by the stories of her past.
However, an odd event during Passover transports Hannah back in time, and she finds herself in Poland in 1942 as Chaya, a young orphan. Even though she is now a young Polish Jew, she retains all of her knowledge and understanding from her life as Hannah. Because of this, Hannah/Chaya is well aware of the dangers that await her community when they are escorted to the camps on Shmuel's wedding day. Hannah may already know of the horrific events that are to come, but the others around her cannot fathom that humans could create so many horrors for other humans, and therefore Chaya's warnings cannot stop the fate that is destined to befall all of those taken to the camps.