Ethical dilemmas are dilemmas of a certain kind of conflict between the rightness or wrongness of actions and the goodness or badness of the consequences of the actions.
What complicates the issue, as it happens, is the difference between duties of omission and duties of commission:
Duties of Omission imply negative rights of others, e.g. abused victim ignored
Duties of Commission imply positive rights of others. e.g., duty to victim
There are some fundamental differences between the two kinds of duties. For a duty of commission to be binding, someone, an agent of the law, i.e., police, judges, prosecutors, and defense attorneys must be able to carry it out. However the ability verses the consequence of responding are often problematic and becomes matters of judgment which can blur the nature of such duties.
If judges, prosecutors, and defense attorney all belong to the “Lawyer’s Club,” they may all consider the “protection” of each other from the consequences of not following the law rather than do the right thing for the victim. This is the kind of dilemma that arises from human limitations, and The Partiality of Friendship, not from the structure of value itself. Now, all in the legal field know they ought to be impartial; that is the essence of legal morality they tell themselves, but this belief is rejected as each resolves that in partiality of friendship there is a moral importance to each other that permits, and perhaps even requires partiality in some circumstances, so as to protect each other from the consequences of their own omissions of justice.
The human condition, which is ignorance and fallibility (especially for those in authority, deceived by their own, as Shakespeare says, "insolence of office"), is what makes the presumption of innocence a good principle, if it is put into practice, for is a good basis for the protection of the innocent, allowing that the lay citizen will have the protection of the law beyond their own familiarity or understanding of it.
Now the situation becomes a dilemma when we want to makes duties of commission matters of law, as in "good Samaritan" laws. The breach and a duty of omission results in a wrong of commission, because of ignoring some empirical physical evidence, i.e., abused victim and the law that protects the victim -- even though it is relatively easy to know that a crime has been committed through empirical evidence, and the law, both of which provides relevant evidence of the crime, but the agents turn a blind eye to both.
This sort of a breach of a duty of commission results in a wrong of omission, which by its very nature produces no causal effects due to the agent. This means we often will never even know that a wrong has been committed if the evidence is ignored, and the law is not followed, and nobody notices. The Minute Order will simply read “Motion Denied” and no one, apart from the agents; will ever know that a wrong was involved.
This is important point to consider in relation to the nature of law. Someone who is prosecuted for not being a "good Samaritan" is not guiltier than the unnoticed callous agents, but is simply more unlucky. Legal sanctions should not fall more heavily on the unlucky than on the guilty. That makes for a bad law.
Duties of commission, however, where it is not known, or ignored, about a prior positive obligation of the victim to do the right thing, are about matters that by their nature may produce not enough evidence, or even false evidence that a wrong has occurred, which means we can never know how many of the guilty, evenly grossly guilty like the callous agents, escape the consequences of their behavior. Furthermore, since ability and consequences cloud the nature of duties of commission, it becomes very easy for agents to distort the evidence or to unfairly second-guess a victim who did the right thing and throw that victim to the prosecutorial wolves, who, as they now operate, go for convictions rather than the truth, and would be perfectly happy to portray the victim who did the right thing as a dangerous violator of the law.
The whole project of examining moral dilemmas is a relatively modern one. We don't find it in Plato or Aristotle who propounded relativism. With them, as in life, what we just really want to know is what a person is like morally -- are they a good person or a bad person? If they are a good person, we want to believe they will try to do the right thing, and the occurrence of dilemmas will not subtract from their goodness.
Most of us do not come across dire situations that present a moral dilemma, but it is always a very interesting exercise to consider a dilemma and what our reaction to it may be.
Large scale evils require the cooperation, and conspiracy of the many against the few. A large number of people are just going to go along with the crowd and afraid of being different and/or victimized by the agents themselves. However if even one example can give heart to those, then right action can suddenly produce the best effects.