OOC:
Neither do I know how spelunkers or mountain climbers do it. I did imagine hammering a new piton every feet of 10 feet wide wall would be a possibility and with "Climber's Kit" it wouldn't even require ability check. Anyway, rope+piton is something I do understand and can easy narrate.
Jim hammers a piton into the wall, fix one end of the rope and throw the other end to Haaroo, it falls into the pit first time, but on repeated attempt Haaroo catch it. Haaroo, Nebula and Shara hold the other end of the rope, while Jim makes it down the rope.
However. When he is in the air just above blade trap, blades come out of the wall, cutting the ropes. Jim, trying to escape as much as he can ends just next to the open pit. There is also a few foots space for him where he think blades will not get him.
Haaroo, Nebula and Shara all fall prone as they did not expect rope to bet cut.
OOC:
You know what Jim have to do - dex save with advantage and take half of half if pass or half of the damage rolled due to his feat
It is obvious for Jim and evident for others that blades triggered when Jim was in the middle of the trap. Jim recall that it is exactly the same position (except for vertical dimension) when trap triggered. He is 100% sure he did not touch anything to trigger the trap.
Jim - your 50 feet rope is now a 40 feet long. And single piton still there, but you are on this side of the blades trap
