You might be missing the point. Eridan. [Said so sourly!! But he gives pause at the next question, because in fact he does had a slightly-less-than-merely-hypothetical method in mind.]

I'd inject you with specific nanobots, all indescribably small and all programmed with a very precise command. Only on my word would they begin to dissemble your brainstem, and work upwards from there. Only on my word, would they kill you.

You'd have to live with the knowledge that I could destroy you whenever I felt the whim

[He smirks, and that could be nearly audible in itself.]

How many hours a day do you spend thinking about me, or things directly related to me?