Quote 4
So he was deserted. The whole world was clamouring: Kill yourself, kill yourself, for our sakes […] now that he was quite alone, condemned, deserted, as those who are about to die are alone, there was a luxury in it, an isolation full of sublimity; a freedom which the attached can never know (4.93).
In spite of having horrific visions, Septimus doesn’t want to die. He believes the world wants him to die because he’s a living reminder of what war does to people and that it’s not all about being a hero.
Quote 5
Miracles, revelations, agonies, loneliness, falling through the sea, down, down into the flames, all were burnt out, for he had a sense, as he watched Rezia trimming the straw hat for Mrs Peters, of a coverlet of flowers (5.109)
Septimus has a vision of bursting into flames. Even sitting in the calm of his room watching Rezia work, he feels completely alone and is disturbed by visions of death.
Quote 6
Septimus was one of the first to volunteer. He went to France to save an England which consisted almost entirely of Shakespeare's plays and Miss Isabel Pole in a green dress walking in a square. There in the trenches the change which Mr Brewer desired when he advised football was produced instantly; he developed manliness […]. (4.89)
Septimus joins the war believing that it will make him a man and that it will prove his commitment to all things British. His idea of England is very limited, but he wants to be the hero and preserve what matters to people like Isabel Pole.