I already know how to kill someone with a knife.

[He pulls out his blade again, staring at his reflection in the cold metal.]

...I got this on my tenth birthday. I felt for just the right spot, and I slit the throats of ten prisoners.

[And he hadn't felt a thing whilst doing it.]

They were my candles. Sir said if I didn't blow them all out I wouldn't get my wish... but I didn't care for the wish. My wishes never come true. I was only doing what I was told.