Tins, boxes, bottles, shapes and too vague to know;
A mirror smashed, the mattress from a bed;
There are several disturbing implications about these objects that the soldier encounters underground. Firstly, they showcase the ways in which soldiers had to attempt to make a life in abhorrent conditions. The process of war does not solely involve combat. There could be long stretches of time between battles in which soldiers trained, worked to fortify defenses, and waited. Supplies such as the ones present in this passage are evidence of a time between battles.
A mirror is a symbol for vanity and self-care, and a bed mattress represents comfort, (a rare privilege for soldiers during active duty). The smashed and abandoned state of these objects leaves a sense of vulnerability because war can intrude upon any living situation.
The rosy gloom of battle overhead.
This line stands out because of its contradictory description. The soldier romanticizes the battle overhead even while acknowledging its gloom. The war-ravaged world overhead is made idyllic in this line by the color "rosy." Furthering the comparison of the tunnel with hell, the battle is located overhead (in other words, towards the heavens). The word "overhead" also rhymes with the earlier word "bed," implying a dreamlike comfort.
He climbed through darkness to the twilight air,
Unloading hell behind him step by step.
In the final lines of the poem, the soldier leaves the underground hell and makes his way to the surface. There is a clear sense of relief in the exchange of darkness for twilight air. Twilight means the time of day before sunrise or after sunset. Because of the gloom of the battle and the soldier's lack of sleep, the differentiation between day and night time has been altered, despite the mention of dawn. There is no escaping the darkness and horror that the soldier experienced in the tunnel. In a sense, he is just exchanging one hell for another.
