Well, the opening FMV is clearly not the dream she had though, because in her dream she goes running off after Squall and doesn't find him, while in the opening FMV, she's standing quite still and ends up in Squalls arms. Of course, that fact means that it can't be part of the ending section either.

Let's just say it was an artful FMV by Square not meant to depict any literal event, but rather to serve as a nice little opening, portraying the themes of the game etc.