Sherlock says, "The Cave of Unpleasant Surprises."
Bella unrolls it and sits. "You want to drive or should I?"
The carpet rises.
It is not such an incredibly long flight, and the cave is quite visible from the air.
"That sure looks like a cave," says Bella, descending cautiously.
"It is one," says Sherlock. "Apart from that, its contents and nature are not extremely consistent."
"Okay." Bella pauses the carpet, and carefully casts a spell of invisibility on the both of them. And then she descends the carpet the rest of the way, and rolls it up, and puts it behind a rock.
Bella swallows and goes in after her, each hand on the opposite wrist ready to pull something out of a sleeve.
It's called the Cave of Unpleasant Surprises for a reason. Sherlock goes in expecting to be unpleasantly surprised. She keeps a little ahead of Bella, but not too far, in case something unpleasant comes at them from a surprising direction.
The cave narrows to a tunnel just barely wide enough for them to proceed single file.
Bella follows Sherlock in for twelve steps, and then is swallowed up by the floor with a yelp. The floor closes after her. It doesn't dampen the sound of her in her armor clattering to uncharitably distant ground, or her whimpering the words of her healing spells.
Sherlock is unpleasantly surprised!
The first thing she tries is stepping just where Bella was. She doesn't expect it to work.
Oh, also, there's a wall back the way they came now.
"Sherlock?" says Bella's quavering voice.
"Sherlock, where'd you go?" Bella asks, overlapping enough of Sherlock's sentence to make it clear that the floor is soundproof in one direction.