Papyrus startles, eyesockets widening as he takes in the unusually raw expression on his brother's face.

"You're okay," he realizes, or confirms. "You're..."

If there's been any question whether Papyrus at least half-believed the ruse, well, the surprise and relief crossing his face now might put those to rest. He tries for a shaky smile to break the mood of their unwelcome shocks, and to soften his words.

"Sorry, Sans, you're - you are very good at pretending. I'm sure they didn't suspect a thing!" That's something, but likely not anymore reassuring than being scared in an awful situation not-alone, so he follows with, "you know what's going on?"