"True. But you all have - you have proper lives, here and now. I don't know how to stop the dreams you have, for those who want them stopped. I don't know why I'm back, or what they mean. You know me, but I can't do anything for you."
It's clear this is the heart of what's paining him. Even when he made the wrong choice, back in his own time, it was his choice to make. He had options and actions available to him.