Sans' pov
"Papyrus can't know or... did you tell him last time there was a Genocide Route?" "There wasn't one. Why can't I tell Papyrus." "Papyrus' isn't supposed to know. Just the Sans in the Sans spot."
Tem quickly nods and leaves.
Why...
"Blue! Where did you put all my mustard?"
I chuckle. I didn't know that Blue placed it somewhere before I came. I run over to Papyrus with a big happy grin on my skull and star eyes.
Papyrus can't know. He shouldn't.
"Mweh heh heh! I the Magnificent Sans shall not tell you! You'll get sick of it you know. I worry for ya."

I can tell he's thinking 'What's up with you?' Or, 'What are you hiding Blue and I know it's not just my mustard.'