>>8937980i dunno dude. Only way to do it without adrenaline and fear is by murdering someone in their sleep or being one of those cults where they love their god so much they'll freely take their lives.
If you're getting your blood from the battlefield, that's far more tortureous than getting captured and then being sacrificed. Even just waiting to get slaughtered is one of the worst things a human can handle.
War is hell.
also, having your neck cut is far less painful and a much quicker way to die than bleeding to death on the battlefield from a stomach wound. or arm being blown off. or getting ripped in half with many bullets or shrapnel. Seconds vs minutes/hours.