Complex sentence: The passageway was discovered by the Nazis, however, and unable to return via that route, he and Zuckerman were trapped on the aryan side while the fighting raged and the ghetto burned.
Split into simpler sentences: The passageway was discovered by the Nazis, however. Unable to return via that route, he and Zuckerman were trapped on the aryan side while the fighting raged and the ghetto burned.