"So you ended up here to get away from the King and Queen?" Sans asked as he slowly processed everything he'd been told. Gaster nodded in reply to the question, and the small skeleton's face suddenly lit up like fireworks. "Wait... So you've been to the Underground?! What do humans look like? Were they really strong? Did... did you ever have to fight a human?"
"Bro, calm down," Papyrus replied with a slightly relieved laugh. "Yes, he's been to the Underground several times."
"I want to go there!" Sans cheered, pulling the blanket from over his head. Gaster smiled and set down his mug as he felt Papyrus glaring daggers at him suddenly. "Is there a way we can go Mister Gaster? Please?"
"Absolutely not," Papyrus growled.
"Papyrus, I want to do this for the child. Alphys... Perhaps she will help. After all, she never told the king of my treason. At least, not in this time..." Sans looked down in disappointment, though it was evident he only understood half of the conversation. Papyrus let out a soft sigh.
"Fine, we can go to the lab and get your supplies. I'll call Undyne and-"
"But brother, I want to come with!"
"No! You are going to stay here where it is safe!"
"But Papyrus-"
"'But' nothing! The lab is very dangerous and I won't risk you!" Sans's eyelights dimmed and shifted away from his brother. This was the first time he'd been yelled at. Even when he'd traveled to the castle alone or went out after dark to play in the snow, Papyrus was never much more than a bit stern. He noticed this and felt his heart drop out of his chest.
"S...S-Sans, I... I'm so sorry," he mumbled out, breaking the silence that came over the three. "You don't understand the dangers we've put ourselves into, little bro... You're the only purity left in my life. Gaster, Undyne, Napstablook... All of us could be hauled away and killed for what we've done. I can't... I won't let you follow in my footsteps."
"But brother, I'm stronger now," Sans replied with a glimmer of hope. His eyelights were almost impossible to see as tears streamed down his cheekbones. "I might be smaller than you all but I can handle it! Even if my HP is low..." He winced as he brought up the fatal flaw. "I want to prove it Papyrus... I want to be helpful."
"Give him a chance," Gaster added. "We can test him first and make sure he's ready. Then we can go to the lab, and if anything goes wrong you can bring him home." Papyrus let out a slight groan.
"Fine, fine. I'll give it a chance." Sans jumped up excitedly and hugged the tall skeleton tightly. He smiled and hugged back. "We'll do some training tonight and test you tomorrow morning before we leave."
"Thank you thank you thank you! I won't let you down brother, I promise!"
"I know Sans, I know."