Angels in the Mist "Dark"?

Someone recently claimed that Angels in the Mist was "dark." With the exception of a few chapters, I'd always considered it a lighter novel. In that person's defense, if the following passage isn't dark, it's certainly gray. (Modified slightly from the book to stand alone.)

Madeline gasped at a frigid touch on her bare back. William's hand was like ice, and when he spoke, his breath was winter on her cheek. "Careful, Madeline," William said. "That sharp tongue of yours could make me forget the only two reasons you’re still alive." An icy finger ran down her neck. She stifled a cry. "Your blood, and your screams."

"The neighbors will hear," Madeline said, choking on the words. She searched the sidewalk, hoping to find someone she might flag for help, but it was empty. Tears dappled her heaving chest.

No one would save her.

Madeline was alone with a murderer.