My guess would be that he's scared, but probably not overwhelmingly so. I'm basing this off the fact that he's hiding, which can be a sign that he's unsure of your motives (i.e. is she going to pick me up?). Maybe he's not used to being petted.
I've been curious about this binky away thing too because Billy does it all the time. He doesn't like to be touched although he will tolerate it if he's in a lazy mood. If he's playing and I try to pet him, he 1) pushes me out of the way with his face, 2) pushes me with his front paws (precursor to boxing) or 3) binkies away.
The point that your bunny is at right now sounds a lot like where Billy was before we started petting him daily. Billy would also binky and run off, but most of the time he would only hop a few steps out of reach and give me the evil eye. I really think Billy was a little scared though, because he wasn't used to being petted and he didn't know if I was going to try to pick him up. After we started petting him every day (mostly during treat time) he got used to it and now just gives me attitude
Essentially he's moved on from being scared when I pet him, to being angry when I pet him...although sometimes if I'm lucky he will bow his head down and receive pets :biggrin2:
So, at this point I think your foster is a little scared...although probably more unsure than scared. I think if you work with him daily and pet him a few times (maybe while giving him treats) he will understand that you're not going to do anything to hurt him and he won't run away anymore. The binky thing I still don't understand though!