Morality Can Be Situational Though Some Are Rigid
There are people who value their own personal morality above all else. To these people, it is better that a terrorist nuclear weapon (as an extreme case) detonate in a major city (even a city of their own nation) than that they themselves take any action that would violate their own moral code.
This is one of those little puzzles that can be asked. You have before you a terrorist who knows where the bomb is, he will not speak Voluntarily. Will you do what you have to do?
For some, the answer is that they will spend the time appealing to this mass murdering wannabe's "better side". Pleading with him and explaining logically that his decision to plant the bomb and start its countdown to detonation is wrong. Obviously if they do this, the murdering wannabe will see the error of his ways and reveal the bomb's location.
If not, such individuals are content that their moral code is intact . . . the blood of the tens, perhaps hundreds, of thousands of their fellow citizens is not on their hands.
I am not wired that way.
As a general rule a prisoner in my hands can be expected to be treated within the rule of law.
But I make exceptions that I consider rational.
Thus if you return to the halcyon days of the live action roleplaying game at Origins this past year, I was willing to apply "coercive" means to convince the prisoner to cooperate. My morality required to do whatever was necessary to safeguard those entrusted to my care, keep them from being killed by the strike the prisoner had called in if at all possible, and thus by any means possible, and get the word out, i.e., make sure someone survives to tell the story of "what happened here". Those conflicting needs obviated my normal "treat the prisoner under the rule of law" morality, because to me the higher morality is to keep those entrusted to my care alive, and that was not limited to those here, but those who might themselves later be killed by escaped zombies or infected to become zombies. To me, that was a higher morality.
There is, however, an acceptance that the law will probably not see it that way. The "Men in the Silk Hats" safe in their moral "gilded towers" can afford to be rigid in their morality and look with disdain on their inferiors who shed blood to keep them safe.
You should also note that when the "crisis" passed, i.e., we found a pilot, the status of the prisoner immediately changed back to prisoner rather than potential victim. At the crisis point, where I had to have his cooperation to save those entrusted to my care, I was quite willing to accept that the "Gentlemen in the Silk Hats" would do their best to have me incarcerated for the remainder of my days for doing what had to be done so that they could raise their noses and sneer their disdain. Once that Crisis point was passed, however, I would do all I could to bring "the prisoner" out (and did), even though he would tell the tale of my treatment of him in that moment of Crisis.
So, if an Al Qaida wannabe is before me with the knowledge of where a nuclear weapon, or even a chemical or biological agent is, that will attack civilians, the next few time intervals of his life will seem unbearably long, and the remainder of his life might require extensive surgical care, and I might spend the rest of my life in prison. But if the attack was stopped, the lives of fellow citizens who are completely unknown to me are saved, I would consider it worthwhile.