I hate to say this, but it was about time for Sasaki to die. The death flags over his head were waving like crazy since he survived the first blast while fighting with Hijikata. And this arc couldn't end without a sacrifice. But Christ almighty, this was a sad death. Someone give Nobume a hug. I wonder what will happen to her now. As Sasaki said, she has plenty of friends with whom she can be now.