The Trauma of War
Sassoon himself was treated for shell shock, a term whose scope has expanded today into the diagnoses of post-traumatic stress disorder. "The Rear-Guard" references this mental and psychological stress both in its form and content. The uneven rhyme scheme and stanza lengths contribute to a sense of disorientation, as do the occasional lapses in meter. In the poem, the soldier's sleep-deprived and bitter frustration comes to a head when he kicks a sleeping man who turns out to be dead. After this, the soldier's PTSD becomes apparent when he is included in the description of "dazed, muttering creatures underground / Who hear the boom of shells in muffled sound" (Lines 21-22).
Dehumanization
Several descriptions demonstrate the dehumanization that occurs during wartime. When the soldier making his way through the tunnel encounters what he assumes is a sleeping figure, his desperation and lack of sleep lead him to act violently toward the person. This section reads, "Savage, he kicked a soft, unanswering heap" (Line 14). Because of his experience, the soldier has been reduced to a savage: something fierce, violent, and uncontrolled. What was before referred to as "someone" and "the sleeper" is now "a soft, unanswering heap" (Lines 8, 10, and 14). The dead soldier is objectified and subsequently referred to by individual and disconnected parts of his body.
Hell
The underground tunnel is compared to hell in the poem. Despite the violence occurring in the battle overhead, the battle is a romantic ideal compared to the dark isolation and terror of the tunnel. For example, the atmosphere of the battle is described as a "rosy gloom," pairing something romantic with darkness and depression (Line 7). With only the dead for company, the soldier must stagger on despite not knowing the location of headquarters and an entrance to the world above. The soldier undergoes a kind of mental unraveling made apparent when he is included among "the dazed, muttering creatures underground / Who hear the boom of shells in muffled sound" (Lines 21-22). When the soldier finally begins to climb out of the tunnel, he "unloads hell" behind him step by step. In other words, by reentering the world above, the soldier feels he is slowly leaving behind his hellish experiences underground. However, it is implied that a different kind of hell (the horrors of battle) awaits him aboveground.
