Elmon and saving the Knight when you unlock the Cursed Wheel

I'm not sure how to ask this without some story spoilers so just through a general Spoiler tag on it.

So, I'm on the quest in B4F and just unlocked the Cursed Wheel. I went back in to try the same point where it says "someone must go with her". However I don't have any new option, just send Elmon or the other adventure (fails) or everyone, or just the Craftsmen.

If I send her in again the knight still dies? I don't have an option to send someone with her that I can see. I did the lighter shields quests with the soldiers and saved them from the cave in earlier which i read in another thread was connected, but past that I can't figure out how to save that Knight that's on the wall; can anyone point me in the right direction?

EDIT: Navaliia had the right move this time. I needed to have the upgraded defenders guard the Warped One on B1F and no one dies that way and they'll move to help save the knight on B4F when you take the new choice with Elmon. I will still argue that needed a bit more prompting in game (most of the stuff you need to do is pretty well laid out; shields, sabotons, etc) but I saved the knight and can move on.