instincts vs fetch trap

"Nothing here," I said, and rapped my knuckles on the side of the tower, eliciting the dull thump of a very solid object. "Maybe the trolls just wanted to fight with their backs to something solid. I might have to go all the way around checking for-"
Without any warning at all the ice of the tower parted. An archway appeared, the ice that had hidden it flowing seamlessly into the rest of the tower. The interior of the tower was all shadows and slowly shifting lights that did little to provide any illumination. Inside was nothing but a spiral staircase, winding counterclockwise up through the spire.
I glanced from the archway to my chilled fingers and back. "Next time, I guess I'll just knock."
"Come on," Charity said. She shifted her grip on the war hammer, holding it at something like high port arms, handle parallel to her spine, heavy head ready to descend. "We have to hurry."
Thomas and Murphy turned to join us at the door.
An idle, puzzled sense of familiarity gave way to my instincts' furious warning. Fetches were the masters of the sucker punch. Like the Bucky-fetch who had jumped us just as we opened the doors to the theater, they knew how to position themselves to attack just as their enemies focused their attention on some kind of distraction.
The suddenly opened doorway was it.
Mounds of bones around the courtyard exploded into motion. Fetches hurtled at us over the ground. There weren't three of them, either-there were dozens.


Proven Guilty Chapter 37, Page 302