^
I think both of it a little, though she didn't seemed to shocked and I'm sure she has began to see him as a (hot!) man even from the time she was his "prisoner"... little stockholm syndrome (I even think to make 1 video on Muse's song "stockholm syndrome", because both of them where kind of prisoner to each other and developed feelings)
I'm sure she's already has some feelings but wasn't waiting/ready for kiss but she definitely liked it in that last scene she was clearly thinking about him and maybe in that very moment was realizing her feelings... I sure there will be few different stages in that realization and their relationship, first some kind of twisted (as Bellamy said) gravity, then more and more

now I'm starting new video and will share soon