Han Li and Li Shuanwei spoke till the walkie-talkie form became nearly transparent. They spoke about the random things. The simple comprehension Han Li had of what the world was and what a human's life was.
Nihilism is the belief that nothing in the world has a real existence and that life is meaningless. Li Shuanwei embodied this in his very being; he was somewhat similar to Han Li himself, just that he lacked the drive or desire to achieve meaning in the meaningless.
He believed a life that was temporary was worthless, and Han Li believed so, too, but more than that, he believed that achieving immortality would change that.
Li Shuanwei also thought similarly, but when Han Li curiously asked why he didn't actively seek such a thing while being so talented, he only had one answer.