What's the point with that quite lackluster story in Endwalker?

[Xirean]

Personally, I couldn't understand why there was this gaping hole standing open long enough for 2 people to ride on dogs from below and across the platform but it never occurred to Emet-Selch to grab Hythlo, snap to conjure his flying horse and exit the same way.

Or.....teleport. Which they do constantly throughout that dungeon....