why was SALT in the operating room in the end. Did she die?

It was pretty clear...watch the movie again.

"I saw you... I saw you in an orange grove."

She was under sedation and being told/reliving the story of the twins.

"If Mad Max Fury Road is an 8 (I gave it a 1). Then I'll use 8 for OK, 9 is better, 10 is best."