[spoilers] Lucas. Just Lucas.

[Belle]

Binkie and Byatil, great analyses of 8.4! waw, you both really dig into every second of what we see/saw!

I think 'Roushanka' is the name op the prison were Lucas was held.
And I think Oleg is implying that, even though Lucas isn't physically captured any more, he's mentally still a prisoner and Oleg still has an enormous impact on Lucas.
As Binkie and Byatil both prooved with their analyses, there is much truth in this statement.
As for the Lucas is John sh*t, well, there really is no plausible explanation as to why we should believe a single aspect about it.
Even if Lucas suffered from trauma (which he undoubtably did) and had 'forgotten' he was John, there are too many plotholes in the story to be taken serious by us.
The picture Beth retrieved in merely minutes (as pointed out by many in posts above) is just one of them.
Then there is Maya:
You don't simply forget about 'the love of your life', even if you don't actually realise anymore who it was (due to memorieblocking, wich I can accept) you must have dreams about them or even flashbacks, or the faint feeling of something missing. And we never got any hints of that being the case, so the writers expect us to take that in just like that, as if we don't have a decent brain of our own.
As BravoNine said, it's not so much the fact that Lucas was someone else (though I still have reasonable doubts someone like Lucas could have been and rebecame someone like John) , it's how they made us see that story that's lacking spine, what so ever.