Adam giving up what was left of his immortality to save Matt and Charlie was a fantastic ending to this story.

Thanks! I'm so glad you thought so. I'd already raised the prospect of Adam living on past Matt's death and so I had to deal with that. It seemed the best way for the story and for Adam in the long run.

And Matt's willingness to die to stop Syler was the ultimate act of redemption.

I didn't want to finish without Matt having done what he could to make up for his actions, both for him and for the readers. He needed to do that before he could move on.