Back in the present, Mettaton yelled, "Frisk, dear! It's time to go! Frisk?!"
The robot thought the silence was suspicious, so he got off the couch and approached the door.
"Frisk, darling, are you alright in there?" Mettaton asked as he knocked on the door. "You aren't trying to hide from me. Are you? You know you can't hide from Daddy."
When Mettaton didn't hear a response, he twisted open the handle and walked in. Mettaton immediately saw the shoes and shirts piled next to the window. He then looked around and pulled open the bathroom curtain to find Frisk sound asleep in the bathtub with his phone sitting quietly next to his head.
Mettaton sighed, pulled out his phone, and said, "I should have known. You are anemic after all. Just let me call your babysitter."
Mettaton called Burgerpants and told him what was going on. He then teleported there as quickly as he could.
When Burgerpants arrived, Mettaton showed him the sleeping human child lying in the bathtub.
"Adorable, isn't he?" Mettaton said wistfully as he took a picture of Frisk to put on social media.
"Yeah…" Burgerpants said. "So, you want me to take him to your house?"
"No, not yet," Mettaton said while posting the picture. "I want that to be a surprise for him later. I know he'll just love it when I finally show him his room. Taking him there now would ruin it. I want you to watch Frisk and bring him to me once he wakes up."
"So, you want me to just leave him there?"
"You're right. He might get cold."
Mettaton walked out of the room for a moment.
During that time, Burgerpants whispered, "Don't worry, kid. I'll get you out of here somehow. I swear."
"Here, we go," Mettaton said walking back in and covering the sleeping human in the tub with the straitjacket he was threatening him with earlier. "That should keep you from getting too cold. Sleep well, darling."
"Wait, is that a straitjacket?" Burgerpants asked fearfully. "Boss, why do you have a…?"
"Oh, that thing," Mettaton said gesturing at it nonchalantly. "It's just something I borrowed from the local mental health ward to persuade him to behave. He knows now that if he tries to run away again he's going to be sent away to spend what remains of the afternoon with his psychotherapists."
"But I thought getting psychiatric help was supposed to be a good thing…"
"Oh, it is. Frisk would be getting help for all his issues. He just sees it as a bad thing, so I thought I could use it to persuade him to behave until I take him home. And now, he has stopped trying to run away. It's a wonder what a little tough love can do."
Burgerpants stared at Frisk, the bracelet around his wrist, and the straitjacket Mettaton was thoughtlessly using as a blanket. He couldn't suppress a shudder.
"Anyways, Burgie, I'd better go," Mettaton said turning away and creating another trapdoor with his feet. "Remember, when he wakes up, bring him straight to me. If Frisk decides he doesn't want to cooperate, put him in that straitjacket and drop him off at the mental ward over at the hospital. They'll know what to do. Also, be sure he gets plenty of water. Humans die if they get too dehydrated. Understood?"
"Yes, Mettaton," Burgerpants replied. "I understand."
"Splendid, you're really earning your bonus, Burgie!" Mettaton said happily before he finally jumped into the trapdoor.
Once the trapdoor dissolved, Burgerpants sat by the bathtub and pondered until he came up with a plan.
When Burgerpants had that plan, he knelt by the bathtub, teleported the straitjacket away so Frisk wouldn't see it, and shook the sleeping child.
"Frisk, wake up," Burgerpants said quietly. "I need to get you out of here. Please, wake up."
Frisk moaned quietly as his weary eyes opened and said, "Burgerpants? What are you doing here?"
"Long story short," Burgerpants said grabbing his clothes from next to the window and dropping them on Frisk's lap as he stood up. "You fell asleep. Mettaton called me to babysit while he got the show going. Now, we're here, and I have to get you out of here."
"How?" Frisk asked as he pulled on his tank top. "If I go anywhere, Mettaton can find me with this stupid bracelet..."
"Not if he's too distracted to look for you," Burgerpants interrupted.
"What do you mean?" Frisk asked.
"Just listen…" Burgerpants said before revealing his plan to Frisk.