The lieutenant is surprised that he is wounded, because he was not on the battlefield, but he is very calm.
Every soldier knows that he might be wounded at any time in war. War is dangerous, after all. Even if you are not on the battlefield, you are in a war zone. Soldiers know that the risk of wounding, disfigurement, or death, is high. Most soldiers probably figure that they are going to be killed or injured on the battlefield though. It is the most likely place.
That is why the lieutenant in this story was surprised when he was wounded while doing the most mundane of acts—rationing out coffee.
The lieutenant was frowning and serious at this task of division. … when suddenly the lieutenant cried out and looked quickly at a man near him as if he suspected it was a case of personal assault. The others cried out also when they saw blood upon the lieutenant's sleeve.
Everyone is surprised, because they were all engaged in a basic housekeeping task, and far from the battlefield (relatively). When the lieutenant is hit, he reacts calmly. He puts his sword away as best he can, and does not cry out or scream or lose his composure in any way. He is, however, starting to go into a kind of shock. You can tell by his reaction to the sword he was using to sort the coffee.
Turning his eyes from the hostile wood, he looked at the sword as he held it there, and seemed puzzled as to what to do with it, where to put it. … He looked at it in a kind of stupefaction, as if he had been endowed with a trident, a sceptre, or a spade.
Then he has to get his wound looked at. He has the presence of mind and ability to go out to get help, and on the way he gets reminded by an officer that he should have bound the wound first. The officer stops to do it himself with his own handkerchief.
He bound his handkerchief over the wound, scolding away in the meantime. His tone allowed one to think that he was in the habit of being wounded every day.
Finally, the lieutenant arrives at the hospital tent. It is only then that panic sets in. He is afraid that his arm is going to be amputated. The doctor tells him to not be a baby, he won’t lose his arm. The lieutenant is getting more nervous though.
"Let go of me," said the lieutenant, holding back wrathfully, his glance fixed upon the door of the old school-house, as sinister to him as the portals of death.
The lieutenant goes with the doctor because he has no choice. He has to have his arm tended to. The doctor is just telling him what he wants to hear so he will go quietly. He does have his arm amputated. What started out as just sorting coffee turned into the last day the lieutenant was in the war.
The lieutenant keeps his calm through everything until he gets to the reality of the hospital, when it finally becomes real to him. It was only then that he finally snaps. What this story tells us is that any day in your life, things can change in an instant. This is compounded in war, obviously. His life was changed forever that day. One day he was in the war. The next day, he wasn't.