Curiously, I've noticed that ever since I first played Fallout, Killian's assassin in Junktown never actually opens fire. I see in FAQ's that he's supposed to attack first, then you gun him down and Killian hires you to take down Gizmo. It's never worked out that way for me yet, as he just idles there next to Killian for hours, and finally I shoot him in the face to trigger the quest.
Sure, that gets me where I'm going but it feels a bit jarring and out of character that I have to blast this shady looking fellow who hasn't done a thing yet just to activate the quest. Has anyone else noticed this minor quibble?

Odd, it always works fine for me. Have you patched the game?

I patched the game when I borrowed it from a friend, and the one you get from GOG.com is fully patched. Just a strange quirk...hardly a game breaker for me.