I wonder if this has to do with the new melee weapon quality system, but has anyone else noticed that it seems much harder to capture instead of kill raiders now? With my two gun wielders fighting in melee, and the third using the plasteel knife that I started with, I accidentally killed the first three raiders that came along. Usually the first raider is an easy capture that forces me to build a prison early.
Of course, it might also be just because of the knife, before a knife became a starting weapon, I would just have all three of them punch the raiders out.
How are they killed? If they die of 100% blood loss instantly, that's just the game preventing everyone from getting incapacitated. If they die from their torso (or a vital organ, or their head/brain) getting to 0 health, their death was certain and probably preventable by using different (or no) weapons.