OOC:
Nice roll! The DC is exactly 18!
With Mischa secured to your rope like a harness, you hold your breath and and move through the hole to slide down into the sewer pipe, while carrying the heavy ladder and securing Mischa's way as well.
Luckily there is enough light shining in from what you presume to be the end of the sewer pipe. Because you are not able to keep holding on to the torch, nor would it be safe for Mischa to attempt it.
Your agility easily allows to you use the otherwise treacherous slippery footing of the pipe to your advantage. As your acrobatic prowess combined with gravity allows you to control your descent down the curving pipe's slope, you deliberately shift the weight of the ladder to keep your balance steady. Putrid sewer water flows and splashes, covering your feet up to your shins.
When you maneuver around the pipe's bend you
do see its end. The slope then gets steeper and it's hard to keep the rate of Mischa's descent slow. Gravity forces your party to pick up pace.
Ahead, about 4 feet before the end of the pipe, you spot two iron rods protruding upward from the pipe's floor. Flowing filth flows between and around the rods just before it drops into the space beyond the pipe.
In your descent, you know you and Mischa will have just one chance to grab the iron rods. If you fail, gravity will force your party to fall down with the sewer water into into the space beyond the pipe. If you succeed, you can slide the ladder's iron rings over the rods and have a secure way to climb down.
...
As you maneuver close to the rods, you succeed and manage to grab hold of one, and then use your legs to secure yourself to it. Then you pull on Mischa's rope to slow her down enough that she can grab the other rod.
You slip the ladder's rings over the rods and peer out into the space beyond the pipe before dropping the ladder down.