Bribe your guard to let you escape
That was done by PoWs both blue and gray.
At Castle Thunder in Richmond, Virginia, some Yankees didn't have any money but that minor fact didn't stop them. One Yankee approached the Confederate guard on duty and told him that he and three other PoWs would each give $50 in gold if they were permitted to escape. The guard didn't blink and excused himself to consult with the guard outside. Figuring that they would each net $100 in gold, they agreed and told the Yankees that it was a bargain.
That night, the prisoners approached the window to climb out onto the platform where the outside guard stood. From the platform they could descend via staircase to the street below. As the first Yankee approached, the guard inside asked for his money. "Last man has it," he was told. The guard watch as the first man, then the second, then the third, the fourth, the fifth, the sixth and finally the seventh. Finally the guard gave the alarm but not before five men got away. The two who were caught readily identified the two Confederate guards who were bribed.
It is likely that the hapless pair were court martial.
Vigilantibus et non dormientibus jura subveniunt. Molon Labe!