So what is going to happen to Lizzy? The tower is wrecked. Scratch will probably not have another opportunity like this. So what is the value Lizzy? Green Eyes.

Michael makes the observation that Ink has clear green eyes when they confront him in the tower. This very unlike the eyes of the other zombies. In fact, one of the thing people say to check after a close call is the eyes.

Datu says that Samantha has green eyes.

So ink has green eyes
Samantha had green eyes
Lizzy has green eyes.

Is any other eye color mentioned? Do you know the eye color of any other character? I can only think of one. In chapter 1 Michael says Pegs dark eyes drew him to her. Have I missed any?

Are green eyes a genetic marker for something important to the zombies?

Wading further into the deep end, The woman killed at the golf course is a red head. Red heads often have green eyes.