So, at a glance, the choice is picking between guaranteed exhaustion and the chance of a fight detracting from the mission.
However, as noted, ambushers would be most likely to go after you on the way down, or at the destination once you engage in a conflict, so the ascent is a comparably risk-free zone. We also have a chance of fighting rank 2 beasts on the way up, which is every bit as bad as fighting Kang Zihao.
Pulling your body around by your arms while free-climbing a large cliff is also probably str+athletics. If we do encounter an enemy on a sufficiently vertical incline, our mobility and dodge may be pretty strictly limited.
Climbing is also pretty traditionally a strength roll rather than dexterity (moving your entire body around by your hands and all). Athletics is the obvious skill.
Our basic dice pool to climbing is fairly bad, salvaged by our really good athletics. Notably, SCS stops working if we have to climb a 45 degree+ vertical incline, so Crescent's Grace does nothing. Trackless escape works for 8 rounds, a duration measured in seconds to minutes, which, if we're moving vertically, may not actually get us out of sight. For mortals, free-climbing is an intensely risky task. For us, it's probably pretty manageable normally, but there's potentially a non-zero chance of falling and hurting ourselves, and our dice don't really push well against that, particularly if we're attacked or encounter something while climbing instead of walking.
On the other hand, if we have to move away in a dark cave tunnel, we'll A: have the ability to trackless escape more easily, B: have crescent's grace for speed.
[X] Take the tunnel
So, being Cai's minion has meh pay. If we wanted to beat people for money, Hong Lin would be a much better pinata than doing this mission, and it's hardly like the rules Cai set down have any claim to moral superiority or legitimacy besides power and Cai's ability to enforce them, so we can't even say that this would be more justified per-say. A likely similar amount of work would net us 10 sect points, which are equivalent if we want the cash but also let us do a number of things stones can't do.
This individual in question has also robbed a lot of sect disciples and is probably fairly wealthy atm, potentially with stuff she bought from selling the stolen goods (which would be the easy way to track her down really). Handing the person, and presumably their assets, to Cai is working at a loss. We'd get as much from a reasonably challenging mission, face less risk and have a chance for more interesting events or finding things in the wild. If it is Suyin, she's responding to people crippling her with robbery (and potentially just taking her own things back).
It's quite simply not worth it to do the job. It's also quite possibly pretty against the things we stand for. Potentially Cai actually knows this if it is Suyin, and is testing us, though this doesn't feel like her style, though it's possible the close is meant to be somewhat blatant (her basis was also capable of some subtlety at times).
Telling Suyin and getting things to stop for now is in the best interests of everyone involved, but it's very plausible this won't close up simply with that, and we may have to take a stand against Cai if she continues pushing for punishment.
Also, Han Jian's info was a godsend, holy hell we actually know what the fuck's going on now. And yeah, confirmation that Ji Rong was being a bit of a prick--just not as bad as one as he could have been--taking the fines for himself was certainly something that could be intepreted as an insult.
Easily interpreted as such, but, well, the alternative is Cai taking them, while not actively working for it. Her justification here is incredibly self-serving (it's immoral for Ji Rong to take the fines, so she should take them instead). Meanwhile Xuan Shi directly profited off of the work of enforcement against Ji Rong (actions on her orders at that).
It's... a pretty blatantly off system, and one Ji Rong had no real chance to disagree with at the meeting. It's hard to call him out for that really, especially since the whole enforcing thing seems to require non-Cai cultivators to work for free. Notably, Cai paints herself as the (unelected, unappointed) government of the outer sect, profits off any collection. None of the red cultivators consented to the rules. Cai just took everyone powerful enough to object and pushed them into agreeing and working for her for free.
It's also fairly apparent that he met with Cai and she doesn't really seem to have liked his attitude, shortly before she fucked up his training for a month.
Notably as well, we haven't heard Ji Rong's side of the story. It's eminently possible someone attacked
him in the housing area and he looted them as normal instead of fining them. We also have a very probable situation right here where enforcement isn't necessarily the right thing to do.
One thing I would like to point out is that this person is some how avoiding Cai sight. I don't think our friend would be able to do that a full stage lower. It might be good to warn her about it. But I doubt it is her simply because I cant see her being able to avoid detection. She has no skills in that area and the only floor she should have access to is the 1st unless she is doing 4 quests a week or something.
Cai quite feasibly has no actual anti-stealth art, in this sense assassination might be a relative vulnerability. Alternatively, Cai isn't very likely to go patrolling herself, so randomly finding the person would be a little odd. Like, is she telling us she actively tried to find this person herself and failed?
Now, if there *is* going to be an attempt to attack Ling Qi... well, it seems a bit... rash, to be honest. What would be the gain? And it's likely that it'd require either several lower cultivators of Kang Zihao himself to accomplish - would Zihao be willing to waste the time to ambush a servant of the hated Bai himself? Perhaps "Ling Qi fails a sect mission" is enough to invest some effort? I don't recall there really being a penalty though.
Take an eye or an arm as a message to Meizhen, try to pull her into a fight via us, other stereotypically villainous behavior.