So it goes

Soldiers are trained to have the mentality "kill or be killed", so that they don't hesitate to kill another soldier. During war soldiers see, so much death around them which makes it hard to understand how they are able to keep fighting, and not just give up. Throughout Slaughterhouse 5 "so it goes" is repeated after every death reflecting the lack of care or interest the author and character has about death. Does having the "so it goes" mentality help soldiers get through war, and help Billy Pilgrim get through all the death that he has witnessed because it leaves them untouched by the feeling of loss?