I think that it is significant that there are not many flashbacks used in O'Flaherty's short story. It is significant because the sniper is shown to be singular in mission. Nothing can distract him from what he is charged with doing. He focuses on his target. He is hit. He kills out of collateral damage. He denies himself food because he is "too excited." All of these realities of his characterization focuses on the fact that he is driven to accomplish this mission. If there is any flashback, it actually resides in the mission. The description of the sniper's eyes as being the "eyes of a man who is used to looking at death" is the closest element one has to seeing a flashback invoked by the sniper. Simply put, his lack of flashback reflects such a singularity of mission, something that shows his drive. It is also reflective of the idea that the sniper does not possess the capacity to emotionally reflect and ruminate about anything other than the mission. It is for this reason that his repudiation of this at the end is significant. The lack of flashbacks reflected in his present is something that one can surmise will be replaced by flashbacks of regret and remorse with the ending of the short story. In this, while the sniper might not possess the emotional capacity to engage in flashback prior to his mission being accomplished, it is clear that he will be able to do just that in the most agonizing of manners with the mission having come to an end.