So, Vizzini’s sitting there on a rock with Buttercup on his lap and a knife to her throat, and as Roberts/Westley approaches, he says, “You’re killing her!” prodding with the knife. So. Guilderish standoff. The famous iocaine-powder contest ensues.
Except, Vizzini’s assignment here is to kill her, in circumstances that can provide a pretext for Florin to make war on Guilder. So. Why doesn’t he just do that now? Better yet, kill before his pursuer even catches up with him. And then, unencumbered by his partners or his prey, count on his Sicilian cunning just to slip away from this pirate, whatever his interest in this creature might be.
And he’s supposed to leave her body to be found on the Guilder frontier. It’s easier to get her there if he can make her walk with him rather than dragging her corpse the rest of the way with an angry pirate on his heels. (Well, Fezzic could carry her body pretty easily, but as far as he knows, the man in black already killed Fezzic.)
AND frankly Vizzini thinks he’s waaaay too smart to be beaten in such a contest, so in his eyes it’s an easy win. Losing would be inconceivable, naturally.
Because Bond indicates he knows about Operation Grand Slam, and Goldfinger needs to know how much and who he might have told. Note that in the movie, Bond does not escape from the laser beam – Goldfinger turns it off for this specific reason.
One might also ask why Oddjob bothers with his Hat O’Death rather than just shooting people which is probably quicker. The answer is: what’s the point of being a homicidal supervillain if you can’t do cool stuff like killing people with lasers and slicey hats? Guns are so plebian.
I’m still not certain what Vizzini’s plan was there anyway. The duel of the minds was Westley’s suggestion, yet Vizzini was sitting there calmly with a freaking picnic laid out. I’m not at all clear what his endgame was at that point.
Vizzini’s basic motivation is always the same: to prove that he is smarter than everyone else. It’s in almost every sentence he utters. While he would love to start this war and all, it’s really no comparison with the first goal.
