As disturbing to readers, as the sniper himself, the story provides wonderful vivid verbs. An engaged reader can easily identify the necessity and need the sniper feels in regards to his objective at hand.
Two vivid words which are very effective in the story are hungrily and bitten.
The verbs are found in the following sentences of the story:
He was eating a sandwich hungrily.
He became bitten by remorse.
The verb phrase "eating a sandwich hungrily" provides two very different interpretations. First, his physical hunger is apparent. The sniper has not eaten since morning. Second, the sniper is hungry for the kill (he wishes to eat). He needs it in the same way his body needs nourishment. It seems to be a part necessary to his survival.
The verb "bitten" also provides a dual interpretation. He was bitten by what he had to do. In the beginning, he was hungry for the kill. (A link provided to the earlier mentioning of "eating"). Here, the sniper is bitten by his need to eat by way of his remorse.