User blog comment:Master Moridin/Hallucination + Inconsistency = Confused Mori?/@comment-226878-20151214045405

Camera tricks are common even in live-action. There's a method they use to make it appear as though something far away, is right up next to someone. It's called forced perspective.

The purpose is about creating a response by distorting visual reality. It's a common narrative trick used in anime to stretch the distance between characters so that one can get a running start. This builds suspense and provides suspension of disbelief that the other character can react in time.

For the purpose of an in-story explanation, I honestly believe Yang was never that far away from Mercury. It was the illusion that made her think that part happened. The only part that was real was her attack on Merc.