So, the Emperor used its power to stop Tav from falling to their death after the nautiloid fell apart. This we know. Everyone else "survived" though we don't know how.
We can assume Shadowheart was also saved in a similar manner based on her lack of memory of it and where we found her.
Astarion's pod is right by him. Considering he's largely unharmed, I imagine the Emperor also slowed his fall cos the pod wouldn't be enough to break it.
Wyll and Karlach don't go into detail about the fall at all. Neither seems to have a way to slow their own fall. We can assume the Emperor was involved.
Lae'zel it is uncertain. Githyanki have psionic abilities, but Lae'zel doesn't excel in it. She may have had her fall slowed, but considering the history between illithids and githyanki, it seems unlikely the Emperor would spare her. I can see an argument either way.
What we DO know is that Gale was not saved by the Emperor. He saved himself. He had to actually intentionally call on magic to break his fall so he didn't become a puddle in the dirt. The Emperor did not help him.
I am fascinated by this implication. Was Gale not part of the Emperor's original plans? At what point did the Emperor pull him under the Astral Prism's protection? What made the Emperor decide to, I wonder? Why wasn't he included under the protection from the start?
Such interesting food for thought~
adding to this: perhaps he was saved by the emperor, by somehow keeping him inside the portal therefore in stasis until tav and thus the artefact/emperor finds him?
