Distance = speed X time.

Average speed of an eagle in flight is about 320 Kmph. I estimated that it flew for only 7 seconds (minus time it needs to soar from AS's arm to achieve full spend of 320 kmph.

Distance = 320 times 7 divide by 3600 equals .62km.

They were just about 620 metres apart at that grasslands scene in the final episode.

Was that far?? Hardly. And AS was on his horse. A horse can gallop at about 70kmph. AS can reach her in about 30 seconds. Surely, after all that they have gone through, he can trust her to be away from him, just 30 seconds away?? So, just because they were not in the same frame, they were not 'together'?? 

They were just 620 metres apart, and Ashile Sun would need only 30 seconds to reach her, if the need be.

Thanks! Took me about an hour to check all the info, and do all the calculations, but I felt it was worth it.

We constantly have people who asked us the same question, were they together or not, just because they are not seen in same frame in the final scene.