I just finished watching House, and boy was that ending a doozy. I'll leave out any details/spoilers for those of you who haven't seen it yet, so don't worry. The entire episode was very morally gray, which is both thought provoking and discomforting. It makes you think, "What would I do?" and when you don't know, you get uneasy.
I'll present this dilemma since it's a common thought experiment, not exclusive to House.
As a doctor, you have the ability to end the life of one ill horrible man, an act which will most likely save the lives of a hundred thousand innocent people. If you let the man live, these people will probably die because of his actions. You will most likely not be caught for killing this man, but it's always a possibility. However, it is your duty as a doctor to save lives. What do you do?
Would your actions be different if you were 100% sure it would save lives, or 100% sure you wouldn't get caught?
I won't tell you what happened on House, but beware: read the comments at your own risks. Comments are allowed to contain spoilers about the episode. I'm also not sure what I would do. I may have to stew over it for a while, then I'll add my thoughts to the comments.