"Let's train." Her lips curving into a smirk.
"T-Train for what?" I spluttered, fear flooding my body.
"You'll see at the end, so, let's go." She continues, and just as she turns, I see the ghost of a smile.
"I'm on him in less than a second. The knife in my hand finds its way naturally to the soft under his neck and keeps going until its up to the hilt. He collapses. I rip the knife from its gouge. I leap over the ledge of the wall and sprint for the building." -from the novel you're thinking about reading.