I know what you mean, but on the other hand if she did just one-shot him it would cheapen the boss fight a bit too much. I suspect she thought she'd be able to kill him easily too, but didn't consider
the power of the Elder Brain
, and part of that scene is showing you've got a much bigger threat than just Ketheric Thorm to deal with. Maybe if we saw her power before suddenly she gets stopped by that tentacle thing? But even then, you're taking player agency away to show an NPC winning your fights. It's a difficult one in the balance between gameplay and story.
