Okay, congratulations. You succeeded in nerd-sniping me. I went through all four issues of the AU arc, and the closest thing I could find to a reference to the Ferris wheel kiss is Luna's line "And just why can you and I not do this ourselves? I know a thing or two about powerful yet flawed malefactors" at the bottom of the fourth page of part 2. I skipped over the scenes in the alternate universe and the flashbacks, so it's possible that I missed it. Is that the line you had in mind?