Agreed. Like most all bullies, he's a coward. However, he's also a psychopath. Never bet on the actions of a psychopath. It's like that famous scene in Silence of the Lambs and Red Dragon:
Lecter: If you caught me, by implication you must think you're smarter than me.
Will Graham: I know I'm not smarter than you Dr. Lecter. You had certain disadvantages.
Lecter: WHAT disadvantages?
Will Graham: You're INSANE.
NEVER bet against a psycho. Cowards are afraid to act man to man. Psychos with a finger on the button of a nuke will push that button. He'll push it because he knows there is no American marine with an unobstructed and clear line of sight to his head that's within range.
Lack of direct action doesn't imply we aren't within range for a double tap, merely we may be more patient and perseverant than the bad guy and want to use him as a magnet to draw out the other bad guys.