Whether the help came from Undine or Rey's own memory, the possibility doesn't cross her mind. Can't bring herself to even question it.

She focuses on the reality at present, now that it isn't just Nick's head that's at stake here -- but Rey's, to some extent.

"It needs to go here." She points to the back of her own head. "There's a port in the dura that connects to my brain. I'd do it myself, but the needle is a little bigger than the one my father used, so it's a little tricky."

One of the downsides to improvising with what they have here. That, and the process hurts like hell, but Nick might not like knowing that part.