Ok, this is my thoughts for this scenario. Firstly, well, I'm gonna put aside the fact that it makes no sense.
Secondly, would it be justifiable that those two brothers kidnapped your sister for whatever reason? What did she ever do to them? Was she a bad person? Even if she was, it wouldn't be their job to take the laws into their own hands.
Thirdly, you think it'd be justifiable to hold one of the brother as a hostage in exchange for your sister and torture them? I remember you said,
danyet wrote: So, how about torture? Would you refuse to beat your hostage even though you know that if you did you would be saving the life of your sister? I mean time is running out, since she is buried in a box with very little air left.
Don't you think you're doing the same thing like they're doing to your sister. In another words, it's not justifiable. Just because you have an excuse, it's okay to do so? Well, they have an excuse to kidnap your sister, too. It's just a different one from yours.
Fourthly, if you wouldn't torture that guy for kidnap your sister, was there a chance you would hold your anger for what he did to you? That's why people kidnap others as their hostages for. To torture, to release their anger, to get information and so on. And thus, it's the reason why hostage-taking is never justifiable and you also said,
danyet wrote: but the original question mentions nothing about torture.
don't you think it's already implied? You think people would not torture their hostages to get whatever they need from that person? Yeah, big fat