Mizuki can climb down, or lower himself down in the bucket with the rope- either are valid options, but he should be polite and clean the bucket after if he chooses that one.
It's... oddly hard to tell how deep the well actually is, even if he does dive. He'll get the feeling that it's weirdly clean though- even as he and his presence introduces more impurities (no one's perfectly clean all the time, after all), they get removed automatically. At some point, he'll feel like he's stuck in the middle, unable to go further, and unable to tell how far he's gone. Even backtracking to the surface of the water won't help.
As for "anything beside water"... at the surface where the water meets air is a small ledge. On the left side is... a golden box, embellished with the sun. It looks like something of a similar size used to be beside on the right side.
Re: Solo Exploration!
It's... oddly hard to tell how deep the well actually is, even if he does dive. He'll get the feeling that it's weirdly clean though- even as he and his presence introduces more impurities (no one's perfectly clean all the time, after all), they get removed automatically. At some point, he'll feel like he's stuck in the middle, unable to go further, and unable to tell how far he's gone. Even backtracking to the surface of the water won't help.
As for "anything beside water"... at the surface where the water meets air is a small ledge. On the left side is... a golden box, embellished with the sun. It looks like something of a similar size used to be beside on the right side.