"I have no sympathy for the enemy. I simply love ice." At her disadvantage, she used ice to fight an enemy shielded against ice. It wasn't that she only knew ice magic, just that her love for cold, crystal clear ice was stronger than anything else.
"Do you wish to freeze to death? Or be impaled by an icicle? Either way would be exquisite." She wasn't trying to threaten or bluff. To her, ice magic was her greatest gift to give, and she relished the many ways it could be wielded.