How does the Gerard Duval incident represent a turning point in Paul’s life? What situation does he confront for the first time?

He confronts what it is like to become more "close and personal" with those against whom he is fighting. When Duval dies, Paul feels some sadness and desires to help Paul's family through the war, perhaps by sending them money when he could. His realization that he cannot carry out this promise is followed by a discussion with his friends Kat and Kropp who show him that he did not enjoy the killing and that he found himself in a situation in which he had to kill for survival.