...And now to decide whether I should have Miyako show up at all, since it was another fight easy enough that it was resolved in a single post (Also, cause I'm not sure if Kyubey did his teleporting trick or just ran the entire way, which would make a difference based on how far away the fight was from her)
Well, she probably would go as soon as she felt the primordial arrive. And who said the fight is over with such simple post? Even my previous fight was kind of a fluke, the Primordials aren't meant to be cannon fodder, like you guys are thinking they are. Plus, Kyubey just run there, even if Miyako's house is on the opposite direction of Sora's they shouldn't be more than a mile apart at the time the primordial popped up, since it was way before it attacked Sora. Amara arrived after Kuybey, so if Miyako went there when she Noticed the Primordial at first she should be arriving on time to save Amara from the Primordial's retaliation.
I think there's no reason for her not to go (she would be simply ignoring the possibility that some one might die), but it's your choice nonetheless.
EDIT: I'll post their actions now.