after vladek is released from the p.o.w. camp why is he transported to lublin instead of sosnowiec

Vladek boards a train after he is released, which takes him through occupied Poland towards Sosnowiec, but the train travels past Sosnowiec (now officially part of Germany) and into the German-controlled government of the Reich Protectorate to the east (formerly central Poland). He is finally let off in Lublin, in the heart of the Reich Protectorate.

In Lublin, Vladek is led to a camp of large tents and hears stories about the last train of prisoners that arrived at the camp, from which six hundred Jews were marched into the forest and killed. Jewish authorities in the camp have bribed the guards to release prisoners into the homes of nearby Jews, and Vladek tells them that he has a cousin in Lublin. That night, Vladek leaves his tent to go to the bathroom and a guard begins to shoot at him. Vladek runs immediately back into his tent. The next morning the cousin arrives, and Vladek is set free.