What a terrible creature, torturing such a poor, innocent youth...Ah, do not be afraid, my child. I am Toriel, caretaker of the Ruins...I pass through this place every day to see if anyone has fallen down. You are the first human to come here in a long time. Come! I will guide you through the catacombs.

You wish to know how to return, "home," do you not? Ahead of us lies the end of the RUINS. A one-way exit to the rest of the underground. I am going to destroy it. No one will ever be able to leave again. Now be a good child and go upstairs. Every human that falls down here meets the same fate. I have seen it again and again. They come. They leave. They die. You naive child... If you leave the Ruins... They... ASGORE... will kill you. I am only protecting you, do you understand? Go to your room. Do not try to stop me. This is your final warning!

You pathetic whelp. If you really wanted to free our kind... You could have gone through the barrier after you got ONE SOUL... Taken SIX SOULS from the humans, then free us all... instead just waiting here, meekly waiting for another human to come.