If you wanted the death to be obviously contrived and horrible so as to act as a warning to others, you'd opt for the restaurant scenario. Possibly the author does not remember the "Cold" War. It was always this nasty.
Exactly. The author obviously doesn't understand the way Russian operatives operate. They'd slit your throat right in front of your Momma, and make polite conversation with her while doing it too.
Option:
Mugged and stabbed. No questions asked, stabb him, take wallet. Pure mug gone bad.
people, does anyone watches CSI? Scores of ideas, and noone would link a mureder to Russia.