Even though eating together had been Lan Xichen's idea in the first place, a part of Shen Yuan is surprised that he's actually going through with it because he has low self-esteem and struggles with the idea that people might actually like him unless they're as fucked up as he is.

You know, like Jin Guangyao!

His surprise manifests itself as a wide, happy grin, dignity momentarily forgotten as he stands and reaches for his boots. "I know of a place Lan-gongzi might like. Just follow me."

And if he happens to lead Lan Xichen to the Wilful Machine, to a cafe he and Jin Guangyao have frequented more than once, that is simply a coincidence.