Sans stares up at it for a moment, until he realizes what they're trying to say. His shoulders slump in something like resignation, and he nods miserably. "...determination. yeah."

A force that Sans isn't sure has ever done any good anymore. you'll keep going, just because you think you can. and because you "can"...you "have to" She doesn't need to explain it.

But at least it seems as though they're starting to fully understand where they are. That's genuinely heartening to see, and Sans manages something more like a normal smile. He half turns away, motioning for her to follow. "c'mon. i'll show you around if you follow me. it's...nicer further in, than it is over here. you can see the sky."