does the ends justify the means?

for example: war.

what do you think? i'll even throw in a "what-if."

forget about your duty to your country, your name, and your reputation. say you're a sergeant in an army... say you've taken on prisoners... say one of your prisoners is a pregnant woman... say you find out, beyond any doubt, that this pregnant woman is releasing information about your units location to the enemy... what do you do? this woman is endangering you and your men... does the ends justify the means?

you have no way to lock her up. you're in the middle of the desert and if you ditch her she wont survive. if you ditch her you'll not only be killing her, but also her unborn child...

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i'm really split on this... she's obviously not thinking about the baby if she's doing this... she's obviously not going to be silenced in any way... she's going to continue to put me and my men in danger... i don't know if i would have to balls to pull the trigger.

please also answer my question, do you think war is a necessary way of human life?