That's fair, the family thing is why they keep trying to look out for each other. It's why they spent so long talking, both hoping to convince the other to switch sides. And Sans has so many eyes to be looking out with, of course he'd be even more focused on the task.

Papyrus has an inkling of his brother's intentions here, not least because of the cage of bones forming up around him... Though his thoughts frame it more as, Sans is pulling some turnabout nonsense, an exchange for the Manor business. Thinking his poor little brother, so hurt and confused that he mustn't really know what he's doing, needs to be kept harmless and safe.

But it's not the same at all. Even past his responsibility, even past the pain... Unlike Sans, Papyrus struggles to sleep at the best of times. To be stuck in this place, floating and immune to his own dust, no stimuli to focus on and no ability to escape...?

Stuck alone in the Void, again, but to no purpose...?

"Don't you dare," he screams fear and pain, swinging with the charged bone at the bones of one wall, intent on shattering them.