Kamma: Action and its fruit
Kamma is deed, and deeds ripen. Soldiers come down to the water asking what to become, and are handed three changes to payday and patrol instead. The ripening follows the hand on the spear, not the uniform it wears.
Sīla: Virtue in conduct
Sīla is the training in what body and mouth do. No doctrine gets given to these men, only rules sized to an ordinary day on duty. A change of heart at the river is settled the next morning, when a frightened farmer opens his door to armed men and still keeps his grain.
Adinnādānā veramaṇī: Refraining from taking what is not given
This is the precept against theft. Extortion by violence is its plainest form, since a coin handed over with a sword in view was never given, only moved. What gets surrendered is the daily use of the power to frighten, which is most of what makes the work pay.
Musāvādā veramaṇī: Refraining from false speech
False speech includes the accusation invented for gain. A soldier's word carries weight before a magistrate, so one sentence from that mouth can put a neighbor in chains with no weapon drawn. Letting it go means letting go of the second income, the shakedown that needs only a report.
Santuṭṭhi: Contentment
Santuṭṭhi is satisfaction with what one already has. The pay is fixed and thin, and wanting more is what sends a hand toward a villager's gate in the first place. Enough is a condition of the wanting, and wanting outruns any raise.
Sammā-ājīva: Right livelihood
Right livelihood is earning in a way that does no harm. These men keep their post and are told how to hold it, so the trade is measured by what it does to the people standing in front of them. The early texts judge soldiering more harshly than this answer does, though they weigh it on the same scale.