More detail to the plan than that would be entirely out of character.
"It's definitely complicated. I let other people worry about things like that, normally, but... well, none of them are here." Ylva, for a moment, looks genuinely concerned, and a little lost, but she shakes her head. "No, we'll be fine. And you'll be fine, once you get unstuck. There's got to be another way to get out of it, but... well, I don't know it yet, that's all."
the party can never go back to Sigil and it's mostly Ylva's fault, so
"It's definitely complicated. I let other people worry about things like that, normally, but... well, none of them are here." Ylva, for a moment, looks genuinely concerned, and a little lost, but she shakes her head. "No, we'll be fine. And you'll be fine, once you get unstuck. There's got to be another way to get out of it, but... well, I don't know it yet, that's all."