Okay…so how to get down there safely and make sure she had a way to get out again if necessary?
She climbed back to the basement and stared at the open crates. Kite string and plastic swords. The idea that came to her was so ridiculous, she almost had to laugh; but it was better than nothing.
She set to work. Her hands seemed to know exactly what to do. Sometimes that happened, like when she was helping Leo with the ship’s machinery or drawing architectural plans on the computer. She’d never made anything out of kite string and plastic swords, but it seemed easy, natural. Within minutes she’d used a dozen balls of string and a crateful of swords to create a makeshift rope ladder—a braided line, woven for strength yet not too thick, with swords tied at two-foot intervals to serve as hand- and footholds.
As a test, she tied one end around a support column and leaned on the rope with all her weight. The plastic swords bent under her, but they provided some extra bulk to the knots in the cord, so at least she could keep a better grip.
The ladder wouldn’t win any design awards, but it might get her to the bottom of the cavern safely. First, she stuffed her backpack with the leftover spools of string. She wasn’t sure why, but they were one more resource, and not too heavy.
She headed back to the hole in the mosaic floor. She secured one end of her ladder to the nearest piece of scaffolding, lowered the rope into the cavern, and shinnied down.

The Mark of Athena, Chapter XXXIII