One of the messages of the entire novel is the close interrelation amid life and death.
Linda's death influenced O'Brien's war experience in a way that the reason why he writes the novel is really to make sense of his own life and particularly how his life is related to other people's death.
O'Brien uses Linda's death to convey and illustrate his loss of innocence, due there's love and joviality involved in between both of them; thus when Linda dies, O'Brien's innocence also dies by default.
