If you saw a person who was in excruciating pain, and would never have a chance to get out of the pain, wouldn't you think about mercy killing? There are lots of people who think about it. And there are even doctors that help their patients with suicide because of it.

Yes, but you forgot one slight little thing you swept under the carpet.
The patient gives permission!We don't know for sure who is a locked-in unbeliever. But if we could tell, wouldn't you want to execute them so that they would receive less eternal agony in Hell? I mean, if there wasn't any chance that they would turn and be saved, why let them live longer so that they do more evil to get punished for throughout all eternity. Mercy killing!

Full of assumptions. That makes it
cold-blooded murder, not mercy killing.
Perhaps you should consider the seriousness of not turning to Jesus salvation.

No compelling reason to. Plus you've assumed I need salvation in the first place, which is misleading.
The picture of the pains of Hell that I might paint should be scaring you into examining the facts clearly.

Since I know for a fact you have no idea what happens when we die (if anything), because you haven't died yet to find out, why would it? In fact, because you are so obviously lying so much, why should anybody believe anything you say about anything?
After all, you don't know for a fact that I am entirely wrong. And what if I am not only right, but am not even expressing the hundredth part of how bad it will be?

Are you aware what the Quran says about those that don't follow Allah?