I have to admitt the Warden just is doing her job, and isn't anti-Bern here or anything as I initially thought.
They ask, she honestly replies, if they won't ask in detail first then it's their fault.
As for Polly finally finding her own tongue here, I really don't buy her reasoning, after all the person can be a murderer/rapist or just monster in human skin who would deserve nothing else than being killed and that would be ok with Bern moral code, like she changed mindset about Bloody Mary in the past, but in the end it also might be just a person like Bern who defended or fought for his/her family and just being poor or in some unfortunate event put his/her in such position, and he/she could be tricked into accepting the lashing punishment than doing something else.
Polly can't be lashed cause she had choosen colloseum route.
I doubt it can be the father cause Bern's already paying for him by her own fate.
So by logic it's just some random prisoner who first had agreed to such form of punishment thinking he/she can live through it so he would get out in the most quick way.
And for me Bern won't agree to it if she won't be certain that the person she would have to torture/kill is a really bad one, and I don't think Warden will tell her, but maybe I'm wrong. I think next page Bern will ask about this, she won't get an answer she hoped for, and she will ask about option 1 details how that would be played. Maybe it's similiar to option 3 where torturing and killing someone is just a way of usual punishment there through lashing, that sexual slave is not directly connected to intercourse but maybe to provide just some services like striptease for whole night, but we will see.
Obviously we already know author will not back out from this cause it would mean wasting so many pages and judging how little time passed from beginning of this story, then a few months-one year timeskip is not possible, I think. I wonder if prisoner can mix the usual punishment, let's say 50 lashes per week and after being cured to be ready to fight in colloseum each time than taking whole lashing deal all at once.
And like someone above said since we are in the middle of the chapter about swords(nice it will be 60 pages one than just 30), I hope we will finally move to that soon, judging by the name used and knowledge that the pair of swords are some anti-magical weapons, I bet when used in pair one sword can dispel enchantments/magic with what it cuts/touches, and other makes the owner resistant to magic base attacks/mind tricks etc. And judging by how A rank people fight where the magical weapons are the things making the difference, if Bern would be able to remove that factor from the fights she might have even bigger chances even against 3 opponents who would not know what her swords might do yet, but for not even Bern doesn't know anything about them.