You were at the station in Snowdin, the one nearby the river. Martlet was supposed to be here but she wanted to do something and asked you to fill in for her, and obviously you accepted.

While Martlet is gone, a human enters Snowdin through the Dark Ruins and begins killing everyone they see. (They're doing this as some kind of Justice, trying to avenge his kind, the 5 children before him.) You help to evacuate the monsters before returning to the post.

Eventually, the human reaches your post. You walks up to them and confront them, their eyes covered by their cowboy hat.

They look like they want to start a fight, but suddenly. They begin to... apologize?

💛 "I'm sorry..."

Their apology sounds legitimate, but it doesn't make sense. Why are they apologizing now? You didn't even defeat them in battle, they're just apologizing now after slaughtering all those monsters? It just doesn't make any sense, but he does sound like he does mean it.

💛 "...for killing all those people."