Instances where Last Second Chance happens but is subverted?

And by subversion, I mean the villain actually realizes what s/he did was wrong or does a Heel–Face Turn and doesn't die? It seems like when a villain realizes his mistakes s/he dies anyway.

I can't think of any right now. I really want there to be an episode of Doctor Who where the Doctor tells the evil aliens attacking Earth that he'll give them one last chance to surrender and stop their world-destroying schemes, and he'll help them find a new planet, and then the rest of the episode is about him settling them on a nice, peaceful, resource-rich planet and living happily ever after.

When the writers use the trope, they know the villain is going down. They just want to emphasize that he's beyond saving and the hero made the effort anyway.

In the episode with Vashta Narada (may have spelt it wrong; shadow blokes, eat people, for the most part of the episode go round in a astronaut suit saying "Hey, who turned out the lights?"), they give up when they look up who the Doctor is.