Thou shalt not kill is for people who live in the community, and it is there for the protection of the community, and reverence for life, and the author of life, God. Soldiers, on the other hand, place their lives on the line in order to defend and protect the community from those who would invade, commit rapine, pillage and plunder and inflict suffering. In the name of the community at large, the polity (YOU) the government authorises soldiers to kill in a theatre of war, only. If soldiers kill outside their proper theatre of activity, the War Zone, then they are up for criminal charges, and this has happened quite often (especially recently) ... the prosecution of soldiers for offences against humanity outside their proper place of battle.