I don't know the fright and surprise on Hans face makes me think he didn't expect to die.
I think being insta-stabbed with a blade of pure energy would be a tad shocking, don't you think?
Yup. Still he seemed shocked that his son would stab him. He really thought he wasn't going to die.
Based on the hesitation Han had before he stepped on that rail-less walkway, I think he strongly felt there was a possibility he may die. He and Leia both knew the 'monster' Ben had become, but Han wanted to live up to his promise to bring his son home.
He failed.

