I am absolutely ecstatic that you found Oreo safe and unharmed. I hope you don't mind - I just wanted to share with you some of my experiences with Rio as I think that now Oreo has had a taste of freedom he will be eager for more ...
We got Rio from the Rabbit Residence as a young buck to bond with Mizz. Unfortunately, Mizz died about three months later and Rio just went feral. We found it impossible to contain him, he was a young buck (albeit neutered) with a wanderlust and he could escape from anywhere. When I say that he kept escaping it wasn't as though we didn't care and weren't trying to stop him, we really thought we'd blocked up every hole and every possible escape route. We called him Houdini Bunny because he was just a phenomenal escape artist! I have combat-crawled through nettle and bramble patches after him, stood by a hole I'd cut in a wire-mesh fence for six hours waiting for him to come back (it would have been three hours but my mobile phone went off just as he'd come through the first time), etc. He is a big bunny but he could just manage to get through the smallest gap and could even climb over five-foot high wire mesh fences (which I wouldn't have believed if I hadn't seen it with my own eyes)!
I'm just saying this as I wonder whether you've also got a young buck with a taste for freedom. In which case, just make sure that there is no chink of a gap, fence panel which is a bit lower than the rest, plant pot or compost bin that he can climb on to get over the fence, etc. or he will be there! Rio's done all of those ... and more!
I would add that Rio was subsequently bonded with Bashful and settled down again. Touch wood, he is now happy and the hormones have finally calmed down.
I really hope this doesn't come across as preachy. It's really not intended that way, I just wouldn't want you to go through the fear and frustration that I went through with Rio.
Good night and good luck!