Ambrose Gwinnett Bierce 
One of the Missing [EPUB ebook] 

In Ambrose Bierce’s short story One of the Missing, an orderly for the Union Army undertakes a scouting mission. Preparing to fire on a retreating army, the structure in which he is hiding is suddenly destroyed by cannon fire. When he comes to, he realizes he is completely pinned under the rubble. Making matters worse his own gun, primed and ready to fire, is coincidentally pointing at his head. This story, which originally appeared in The San Francisco Examiner in 1888, spotlights the caprices of war.