[For how still Sayori is, it's like the Monika in the mirror has a mind of her own. She crouches to regard the white heart that appears with some curiosity--and then she looks directly out at the real Sans. Her greeting smile is picturesque.

This, somehow, is more unsettling than what Sayori saw of herself earlier.

She forces a laugh and waves her hand dismissively.] Yeah, it's all sticky and stuff!

You should probably lead the way.

[...]

Not because I'm lost or anything, I just can't cover up any more stupid mirrors we find.

[Yeah, she's lost.]