Complex sentence: On the way there he escapes from the train, along with a Polish woman named Alina, and joins a group of Polish Armia Krajowa partisans, but during his time there he has to keep his Jewish background a secret due to widespread anti-Semitism within the group.
Split into simpler sentences: On the way there he escapes from the train, along with a Polish woman named Alina, and joins a group of Polish Armia Krajowa partisans. During his time there he has to keep his Jewish background a secret due to widespread anti-Semitism within the group.