Why was it good for Jan to steal food food from the Americans?

Jan does not really have much choice in the matter. Edek's condition is getting worse, and Jan has to get the food from somewhere. Because Jan, Edek, and Ruth are located in the American zone of occupation, it is inevitable that they will have to take American food supplies if they are going to survive.
Jan is not too happy about the situation, though. When he is confronted about stealing from American supplies by Captain Greenwood, the military policeman, he breaks down and starts crying. Greenwood gently reminds Jan that he is effectively stealing from his own people, as the American food supplies are meant for them. But Jan stoutly defends his actions to the Captain, saying that he will always steal for his family if they are hungry.
Greenwood counters with one of the Ten Commandments—"Thou shalt not steal"—but it simply does not work for Jan. The confrontation of two radically different moral worldviews in this scene forces us to ask ourselves what we would do in Jan's position. How we answer this question will largely determine whether or not we think that Jan's actions can ever be justified.