His mood is...depressed, to say the least. You decide not to say anything and just quietly walk.
The blizzard gets worse, and you're grateful that the snowflakes don't hit you and the snow doesn't hurt your bare feet, since Sans made it warm for you. You're not sure if you could've endured this otherwise.
The town is empty around you, for now, and you haven't seen anything bad so far, but you're dreading what this is likely to lead to. There are footprints in the snow, leading ahead of you, and they're of many odd shapes and spaced out, like they're from monsters who were running.
You shiver, but not from the cold, and check on Sans. He's not looking around, as if he knows what's going to be there, and he doesn't want to see it again. He's walking with his hood pulled down over his head so you can't see his eye lights clearly, but you can see the grimace and stress in his jaw and teeth.
"don't want to go there again..." he mutters quietly to himself so you can barely hear him.
Suddenly, he stops. Through the blizzard you can see a vast blue barrier wall rising up from the ground, preventing any entry to the other side of town.
"well. looks like it's blocked here," Sans says, and he sounds almost cheerful about it.
"Blocked?"
He shrugs slightly, and doesn't answer.
"Sans?"
He looks down and seems to withdraw into himself and shut down.
You keep calling his name, but he's panting heavily and can't seem to hear you. You consider touching him, but you're too scared. The way he looks right now, with that too-still tension in his body, it feels like he might do anything.
Suddenly you hear a loud "CRACK!" and you look down and notice he's clenching the bones of his right forearm with his left hand way too strongly.
Panicked now, you grab his left hand and try to wrench his hold free.
"Please stop!" you yell.
You don't succeed at all physically because the strength of his grip is far too much for you, but your efforts make him notice you and he suddenly lets go.
He looks puzzled by your actions until his eye lights refocus on you and he seems to comes back to the present.
He shakes his head, chagrined.
"sorry," he says sounding embarrassed.
"I don't want you to do this if it's going to hurt you! We can just go back."
"no," he says, too calmly.
You look dubious, your concern showing.
He takes a deep breath.
"i know i worried you, but i need to show you this," he says, more softly now.
You nod slowly, still worried but not wanting to disagree.
"All right."
He turns and gazes at the wall for a long moment, clearly trying to steel himself, but not able to gather enough willpower yet to actually act.
Cautiously, you comment, "A minute ago you almost sounded happy this is here."
He glances at you and you see him examine your expression carefully.
A long moment goes by, but eventually you sense you passed some kind of test and he answers you.
"i remember what happened here, when everything started, but the truth is i've been blocking off the details to protect my own sanity. i guess that's what this wall is."
You're not sure what to say.
After a moment, he chuckles a little and grins with wry, sad humor.
"that's wall there is lately, right? there's a wall around your soul, a wall around this world, and a wall around the underground and my memories."
He nods at the town around you both, buried in snow and lonely silence.
"me, my people, we've all been trapped here for so long. this place used to be nice, but now all there is here is bad memories that we try to hide from each other and ourselves. the feelings are too awful to share so we trap them behind walls and pretend they don't exist. our lives are a complete clusterfuck of barriers."
He examines the cracks in his radius and ulna, wincing at the pain.
"i wonder sometimes, if the growing cracks in our souls aren't really caused by the players. maybe they're caused by the barriers we've put in our souls, to hide the memories and forget what they did to us and pretend it wasn't as bad as it was, and now it's killing us slowly."
"maybe, no matter how much it hurts, it's time for some of those barriers to start coming down. maybe somewhere in what we tried to forget there's an answer we've been missing."
You look down at the snow, grateful you can't feel the ice coldness of it, trying to think through what he said.
"not sure if any of that made any sense," you hear him say, uncertainty in his voice, clearly wondering if he'd shared too much, or taken the conversation to places you would never be able to relate to.
You say slowly and carefully, "I don't think I've been through anything nearly as bad as you guys, but maybe I can understand a little of how that feels."
"Sometimes I'm not sure how much of the past I can remember either. Sometimes all I have is the feelings, but no memories of what events really caused them. It probably sounds crazy, but sometimes I feel terrified and I have no idea why because nothing bad is happening. It just comes out of nowhere. I couldn't be honest about how I felt with anyone, because they never seemed to understand."
You glance up at him, and are surprised by the intensity of his interest. Maybe he's just grateful for a distraction from whatever horrible memories that the blue wall is protecting.
"There was one person who didn't make me feel like I had to have a wall with them. They were the only one who was like that the whole time I was growing up."
He looks like he recognizes some kind of familiar pattern in what you've said.
"just one?" he asks, his tone hinting at sympathy.
"She was my dog. The brown and white dog, with fluffy ears and a certain pattern on her back. When my family yelled at me and made me feel like crap because they'd fight and blame it on me, I'd crawl into the dog house outside, and hug my dog. She always felt warm, and loving, and she never judged me. She was the only one who ever felt that way, the only one I ever felt safe with in my family. She was my family."
Sans exhales heavily. Some of the tension seems to have left him.
"i know the feeling. sounds like you had it pretty rough. some of the ones you called family weren't really family. you're not alone."
He hesitates.
"Really?" you ask curiously.
"the truth is, i wasn't the happiest monster kid in the underground either. back then it was just one person for me too."
He waves his hand, and all of the townscape and snow is brushed away like a bad dream.
"maybe i can show you this, at least."