Brainstorming: How Did Xerath's Ascension Really Go Down?

http://i.ytimg.com/vi/LXNzTn0XLto/maxresdefault.jpg Okay okay, I know a body of people think the Shurima Event was a literary mess, and that they're still waiting on the expanded Shuriman bios. Putting the negativity aside, I want to talk about the turning point of the Shurima, e.g., Xerath's sabotage of Azir's Ascension. We got these neat images with story snippets attached to them narrating what went down. One could take them for face value, but I remain unsated.

See, the snippets strike me as unreliable; not in the sense that they were poorly done, but that they're purposefully "storybook". They skimp out on vital connecting information, such as the exact nature of the "blast" that claimed Shurima. Sources conflict whether the desert "swallowed" Shurima, as claimed by the snippets, or that the people "were obliterated by a wave of unseen energy, reduced to dust and cast to the winds" as described in Azir's lore. Clearly, not everyone perished, because Azir's bloodline survived (as evident in Sivir) and his whole family was at the top of the Dais of Ascension, the very epicenter of the cataclysm. And how did Renekton and Nasus show up so quickly to confront Xerath, if they were indeed "tricked into staying away from the event" by Xerath beforehand? Did they have an artifact capable of teleporting them? Were they just returning to the city? And where did the sarcophagus, in which they sealed Xerath, come from, if they were in pitched battle? See, this is why I think the snippets don't tell the whole story.

Let's not hate on Riot for this, though. Because I'm that kind of person, I invite you all to help fill in those gaps! There are some amazing minds lurking in these threads, and I call upon you now! This is prime material here; heck, I'm tempted to write fanon! Let's get cracking!