Here the question is what action promotes McCoy's & the hiker's interest. The main purpose of all the hikers was to travel to Nepal and have a "once in a life time experience". It is conceivable that this is consistent with everyone's best interests, while helping the Sadhu is clearly not. Action was ethical. However the fact that McCoy feels guilty reflects that he was unable to promote his long term interest. Hence it becomes ambiguous to justify his actions.
Kantian Ethics: Should abide by the following 2 principles:
*Maxim should become a universal law
*Never treat people simply as means to an end but always at the same time as ends in themselves
In the parable, Stephen says that the hikers would have treated the Sadhu differently if he had been from the same ethnic group as them. However Kantian principle forbids such behaviour. One should treat all equally irrespective of ethnicity, caste, sex etc.
Further, if they were treating the Sadhu as a worthy human being, they should have understood that saving a human life is far more valuable than accomplishing a goal.
Under this principle the action was unethical. However one of the shortcomings to Kantian ethics is that it does not give priority for duties. If as a hiker my foremost duty is to complete my hike then in that case the duty of saving a human life may fall below it. In this case the moral character of a person will tell which duty one must follow.
Veil of Ignorance: The key is that people make decisions based on what is good for their community as a whole, and without regard to their own self-interest (since they operate behind a veil of ignorance and don't know enough about what would benefit them).
Now suppose that all the 3 hiking parties & Sadhu had met before in Nepal before they were given there identities. In this state all wore the Veil as each was unaware of respective roles & upcoming challenges. A case can be made that