Serenity

(...)

6. The Operative kills Dr. Mathias in Serenity

The Operative kills a lot of people to support the evil Alliance in Serenity. That’s his job. But arguably his best kill is at the beginning of the movie, when he kills the doctor who headed the project to weaponize psychic River Tam. He tells the doctor that, in Roman times, when a man had failed as completely as the doctor had, he would fall on his sword.

Doctor Mathias: "Well, unfortunately, I forgot to bring a sword."

The Operative: *produces sword*

That man can plan.

(...)

Click on the link :

http://ca.io9.com/5785538/the-10-perfect-murders-in-science-fiction