Indzihar didn't get her resist electricity during the prep.

Oops, you're right. She got that later.

It looks like Larissa cast (or attempted) 18 spells. She used the rod of empower twice (there was one more use left for the day).

Under normal circumstances, it seems impossible for a medium-level sorceror to run out of spells during a day, let alone during a single fight.

I know I've come very close for a day, but I don't remember how recently. Maybe during the caverns of Laryn.