He betrayed her first, it was he who didn't want her anymore, so she couldn't be blamed for using any means necessary to get her revenge.
...
When Norris Moore woke up, it was completely dark outside.
She opened her eyes and saw a sky full of stars above her. London had severe light pollution, and such a starry night was not visible in the city center. She lay there for a while, appreciating it, then heard footsteps not far away. Slightly turning her face, she saw Sherry White getting out of her car.
Her white down jacket was stained with her blood, evidently, it was Sherry who had moved her to this open space.
Norris was so weak from blood loss that she couldn't even stand, and could only watch as Sherry walked over with a bag of bread and sat in front of her.
"Want some?" Sherry broke off a small piece of bread and asked her.
Norris shook her head, which intensified her dizziness, causing her to wince in pain.
