the use of his language shows that the soldiers are truly alone in a hostile environment. Even nature has turned against them. Even nature is angry at them.
They exist in their own world, and yet, as we can see from the stanza, they seem to scarcely exist at all. Tired and aching, they trudge onwards – the silence offering them enough threat to stay awake, and thus, through Owen’s description, we, as well, are afraid of the silence.