Does Morality Come With Any Solid Lines?

In one of my classes my professor has set up a survivor like game. Basically, it is a series of competitions between two teams where the losing team has to vote someone off. But the game itself isn’t the point. The class is about religion and morality, and the point is to see what people are willing to do to win. In survivor, the one who wins is often the one who is willing to stab people in the back the most, but only if they don’t get caught. My professor wants to show us how the lines we draw around morality get moved and fudged as we find such behaviour beneficial. So, are there any solid lines where morality is concerned? Or can all of the lines we draw be fudged? And, if so, what does that say about morality? What does it say about us as moral agents?