how does teresa die in the death cure book

As with when Thomas had to choose between Brenda and Jorge on the Berg at the end of book two (though he was faking it that time), he had to choose this time, and he was much closer to Brenda, so Teresa had to go. There seemed to be a triangle of sorts between Thomas, Teresa, and Brenda (whether a love triangle or a friendship triangle).The only things that make me understand why she died, and so unceremoniously, are the following points: Chuck and Newt were enough, plus all of the terrible things Thomas had witnessed or had done to him by the organization. There were already enough deaths that posed WICKED as the bad guy. No special words, just a quick goodbye that made her seem irrelevant, when really, she was quite important, or so I thought.

Thomas and Teresa finally re-establish their bond at the end of the book. She seemed good all along, just a little misled. Teresa was easy to become attached to as a character. Has he ever explained why, or might anyone have an idea as to why she was killed? I don't understand why James Dashner chose to kill her off. I don't think I ever distrusted her, though she could be angering at times. I found her to be a really natural character, one whom I grew close to very quickly. Teresa's death almost seemed unnecessary. I just finished The Death Cure, and I don't think I can say that the end of any other trilogy has left me feeling more resolved.

How does teresa die in the death cure book