Harrison + Su Ling - possible outcomes

***SPOILER ALERT***

In the final episode, the MI6 station chief Miller assures Harrison that he has given him all copies of Su Ling's student radical intelligence file; but it turns out he has double crossed him as he is seen placing another copy of the file into an envelope addressed to 'Wild Bill', the CIA station chief.

After that, all you see is Harrison and Su Ling being affectionate during the Moon Festival fireworks. The viewer is left to determine for themselves the outcome for this couple.

What are the possibilities, and what's most likely? Are any of these probable, or something else?

* Wild Bill receives the file but he's already on the way out himself, so he does nothing with it - Harrison & Su Ling = happy ever after in the US.

* Wild Bill receives the file and forwards it on so that Su Ling can never get a student visa for the US; so Harrison resigns from the CIA and makes a life with Su Ling in Singapore.

* Wild Bill receives the file and forwards it on so that Su Ling can never get a student visa for the US; so she and Harrison cannot continue their relationship and they part.

* Somehow Miller never manages to get the file to Wild Bill (but I can't think how this would happen).