How to live in a better world? How to get out of Hell (war, poverty, nature destruction)? To produce a better world implies, as any production, a production cost and therefore to produce a better world implies a specific cost that can be called a moral cost. Indeed the very structure of moral discourse has much to do with the economic semantics. However whereas a fair economy tries to supply benefit for all (in a win-win game), there are some situations where such a mutually advantageous structure is not possible. It is such situations that the paper aims to grasp in particular with the help of the lifeboat thought -experiment. In these situations we are facing the necessity of sacrifice, either sacrifice of others, or self-sacrifice. The paper will also show that the notion of self-sacrifice is able to reconcile the teleological ethical approach with the deontological one.