Board Thread:General Discussion/@comment-30664268-20170420225552/@comment-38557913-20190531012446

BlackfootFerret wrote: User1204 wrote: No one could've placed it there. The ruins were locked since Asriel's death. And yet, Toriel has opened that door several times, to let humans through.

And that's not all. Remember how Toriel said she was going around looking to see if anyone had "fallen down"? All the monsters delivered to Alphy's lab had Fallen Down. And some of them were Vegetoids, creatures Frisk can only encounter in the Ruins.

While only burrowing creatures and ghosts have the power to move between the Underground and the Ruins under their own power, Toriel can open and close that door as often as she pleases.

She opens it to let Sans and Papyrus live with her after all. After they call her. With her number that they have. Huh, that makes sense, but that also raises the possibility that Sans or Papyrus went in, saw the soul that Toriel hadn't found (yet she probably found the body so she knew the child was dead), and took the soul to Asgore. While I don't currently believe that, it could be true.