Baldur's Gate 3 II: The Urge for a Second Playthrough

[Keltest]

Thanks, that helps - how did he end up inside a waypoint? Was that his attempt at escaping the crash?

Yes. He tells you as much when you recruit him, if you ask. He saw the rune and tried to fast travel to it. Not in those words as such, but thats the effect in practice. Between the weakening of his powers and the circumstances of falling to his doom, he didn't do it quite right.

Yeah, you can ask him about that - he says it was his attempt at surviving the fall.

It does all raise the question, why did the nautiloid only pick up tadpole victims with interesting backstories/fabulous heroic powers?

Implicitly, those with above average abilities are the ones that were able to survive, either through their own means or the Guardian's protection.