Paul's voice can be the narrative vehicle in which symbols can communicate some of his own feelings regarding the war experience. When Paul returns to the battlefield, he can talk about how the only "home" he has is the battlefield, and that he will never be able to fully connect to life back at his former home. In terms of the symbol of animals, Paul's voice can once again communicate this in the form of explaining how he is going back to his "cage" which is the front. His voice can convey how he has to go back to being an animal, struggling for survival, finding anything and everything as a means to live.
Expanding on the symbols using Paul's voice in the short story allows for a greater sense of depth to emerge. When Paul's voice appropriates symbolic means of communicating the realities of war, it represents how dehumanizing war actually is. This is a major element of the Remarque work. Being able to expand upon this using Paul as the means of communication can make these symbols more meaningful.