The battle ended with you sparing Papyrus.
The fog cleared and Papyrus makes the bone disappear from his hands a sad look on his face.
"NYOO HOO HOO...I COULDN'T EVEN STOP SOMEONE AS WEAK AS YOU..."
Okay then.
Uncalled for, but whatever.
"UNDYNE'S GOING TO BE SO DISAPPOINTED IN ME...I'LL NEVER JOIN THE ROYAL GUARD...AND MY FRIEND QUANTITY WILL REMAIND STAGNANT..."
Papyrus sounded like he was about to cry and you felt really bad.
So you decided to fake your death.
You had a plan that once Papyrus "delivered you to the capital" and left you, you could just escape afterwards.
"Oh I'm so weak..." You said, making Papyrus lift his head up.
"I think I'm dying...blegg..." You said, falling into the snow and closing your eyes.
Papyrus gasped and stood up.
"OH I DID IT! I DID IT! OH I'M SO HAPPY! I KNEW I COULD IT!"
You heard him quickly run over and inspect you.
"HMMM. NO SOUL YET...OH WELL! I'LL GIVE THEM TO THE GUARDS IN HOTLAND AND TELL UNDYNE AND SANS THE GREAT NEWS!"
Papyrus picked up your body and carried you.
He carried you for quite a while and it was hard to be still for so long.
You heard him talking to someone and you heard rushing water.
Then the air suddenly felt hot before he talked to someone else and handed you off to someone wearing armor.
You then heard Papyrus run away and you heard a new voice.
"Hey bro. It's break time, you wanna go to Muffet's and get some apple cider?"
You heard some metal armor clank together.
"No you're right, too expensive...How about Grillby's?"
You heard more clanking.
"Alright! Cool! I'll just leave the human here and by the time we get back, we'll deliver it's soul to King Asgore."
You heard heavy footsteps walk away and you waited for a few minutes until you opened your eyes.
No one was in sight.
You seemed to be inside a volcano or something due to how hot the air was and because of the pools of lava far below.
You quickly got up and ran to the nearest place that you thought was safe to hide.
Which happened to be a laboratory.
(Hope you enjoyed. Stay tuned for more and have a good day)