After walking for a while, they came across a hole in the melted earth. As they approached it, the baby clearly indicated that it wanted to go down. As Yogiri had guessed, whatever she wanted was underground.

...

They had a rope in their backpack, but there was nothing nearby to fasten it to. He could always kill gravity to get to the bottom safely, but it didn’t seem like a situation that called for such drastic action.

-Volume 8 pages 168 and 169