I think Eto came to die. Here is my reasoning. At the end of chapter 57, Noro said he is going to die first Eto. I thought this was a goodbye but what if they both were on a suicide run (considering Eto's reasoning on why she was there didn't seem right). Eto told Kaneki they were alike. I assumed it meant power our how they thought but, maybe, what she meant was that they both wanted to die in style or just simply die. The most obvious reason is how easily she was taken down. Kaneki is strong but Eto is god mode. Yet, he killed her so quickly. This being said, I am starting to think Eto actually is dead. I have been in denial since I read the chapter but, the more I think of it, she wanted to die. Who else better to kill you than the one you love?