Why was Sharlayan abandoned?

[Iscah]

Finally, and most importantly to me, they allowed people to remain behind in the evacuation if they wished to.

That's the strangest part, if anything. They were on the verge of making contact with Hydaelyn Herself – a phenomenal achievement – and not a single scholar opted to stay behind and complete that research instead of fleeing? Or return at the first possible opportunity once the Garleans had been driven back?