Using a deontological approach we may see something of this sort........
We live within a particular ethical realm in which the norm should be that we all treat each other as ends rather than as means toward an end. If, however, someone were to break the ethical realm and treat another as a means to an end (an unethical actor) -- say for the sake of argument a man is raping a woman at the end of an alleyway -- then we must decide how to act. If we treat the unethical actor as an end (allow him to rape), then we necessarily treat his victim as a means, or allow the unethical actor to treat her as a means to an end. If we interfere, then we treat the woman as a means to an end (as she would want to be treated) but not the rapist. From the prespective of the ethical realm (in Kant's form of deontology), there is no proper solution. When the ethical realm is broken by someone we must act so as to return it to its rightful sphere -- we must treat the unethical actor as a means to an end and stop his behavior with the least force possible.
If we lived in a perfect world it would be unethical to break the precepts of the ethical realm. But this world is not perfect, so it becomes necessary to break those precepts from time to time so as to return to the ethical realm. Such action is technically unethical (manhandling another human being) from the perspective of the ethical realm but not unethical from the larger perspective of how we must act to return things to rights (manhandling a rapist so as to stop the rape).
This perspective, by the way, helps answer all those pesky questions about Nazis at the door.
**knock knock**