- His contact with the dying woman gave him a significant chance of having contracted Ebola.
- Traveling by air would increase the chances that he would spread the disease, if he had it.
- If he had the disease, his chances of surviving in the US were much better than his chances of surviving in Liberia.
- His extended family in Dallas would not have been at risk if it were not for his visit.
- The airfare was non-refundable or refundable only with a penalty.
I do think people have some sort of right of self-preservation. For example, right now the medical care for Duncan is costing vast amounts of money, and I doubt he is in a position to pay the bills. The same money could probably be used by Oxfam to save hundreds of lives. I think it's fine for the man to opt for treatment rather than refusing and dying. In that particular case, it's okay to prefer your own good to the greater good.
But in the case at hand? Was it wrong of him to get on that plane and then interact with his extended family, knowing that if he were carrying Ebola, the alternative was dying in Liberia? If you believe in any right of self-preservation (as I think we all do), it's hard to see where it ends.