"Keep this as a backup.
If there's a vertical section ahead, use it to secure yourself." Tenten pushed the steel cable through the crack. Guy took it, wrapped it around his waist, and tied a sailor's knot.
Then Tenten passed in a cloth bag the size of a fist. It held two of her three remaining iron balls, wrapped in oilpaper. A large "IN" and an arrow had been drawn on the paper in waterproof ink.
"If you run into a door you can't open, put an iron ball into the gap around it or a vent and detonate it.
The arrow on the oilpaper needs to point inward-in the direction you want to blast." As Tenten pushed the bag through, she scraped the skin off a finger against the metal mesh. She wiped her finger on her pants and kept passing things in.
Neji entered the duct behind Guy.
His right wrist was wrapped in bandages, making it awkward to move in the cramped duct. He simply tucked his right hand against his chest and used his left to brace himself as he edged forward.
Chisen followed him. There was no room to maneuver his cane inside the duct, so he took it apart into two sections. He had installed a threaded joint between the handle and the shaft; unscrewing it halved the length. Then he slid the pieces into the sleeve of his white coat and secured them with the elastic cuff.
Tenten went in last. Before entering, she scattered a handful of small stones outside the crack-not randomly, but in a specific pattern. If an outsider approached the crack and stepped on them, the displaced stones would break the pattern, letting them know someone had been there when they came back out.
After a dozen or so