<snip>
It's just a bloody death scene.
If I want to try to setup a Last Words scene, I can. I shouldn't have to plot and plan how to cock-block everything the PCs could do to foil it.
Obviously, when the PC does the unthinkable and tries to heal the NPC, I have a conundrum. Let it wor, or not. And then I have to guage if not letting it work will cause me any further questions from the player or not. Some players wil go "oh, ok, must be hurt to bad, or some other problem" Others will dig and have to know WHY.
But the WHY is NOT something they have a direct right to know. I don't go figuring out where the orc got his weapons from that he used in the last encounter. I don't figure out where he learned his skills. If he has a special ability, I don't go figuring that out.
If there's a special environmental effect occuring in the area, I do not go backtrack exactly how within the rules of the game that an NPC could have caused it to happen (which might have required desiging new spells and items). It just does.
Asking WHY is the player trying to make you gamespeak your way to justify the exact reason the situation is as such. And sometimes, that information just isn't relevant or even appropriate for the player to know.
<snip>
To the DM, it’s just a bloody death scene. For the players it is a situation where their expectations for in-game effect do not match with observed effect. As far as the players are concerned this could be a CLUE. Is all healing affected? Perhaps the area is tied to the Negative Material Plane and healing is strongly suppressed . Perhaps the “dying man” isn’t really a dying man? Is he a form of undead/illiusion/possession of his dead body by some other THING? Perhaps the PCs aren’t actually in the environment they think they are – is it a dream or alternate reality?
When the player questions why he is trying to make sense and remove the inconsistency between expectation and observed effect and work out the expected consequence for the environmental inconsistency.