The second slash is firmly landed onto Sans's body. It hurts so bad. Thinking that he has failed his brother, and that he couldn't defeat Chara, Sans is in despair. Why prolong the pain any further!? He's just about to throw in the towel when... all of a sudden, he hears someone's familiar whispering... "Don't give up... You can still avenge Papyrus..." "Don't give up..." "Don't give up..." "Don't give up..." And for some reason... Sans finds the will to go on. He doesn't admit death or defeat just yet. He must push on just a little longer. He will give Chara what she deserves, for real. Even if that means... "...we have to stand here until the end of time."