After much thought, I'm going to have to disagree. It is much more important that there be dramatic tension from scene to scene, a reason to want to see the next scene, than the actual logic of the scene.
Sometimes believability requires things to be less realistic.
TERMINATOR, in my opinion, has one of the biggest gaps in logic and cause and effect of any film. And yet it holds no bearing on the film.
Many people are quick to point out the paradox that the time-travel creates is a big flaw in logic of THE TERMINATOR. If the Terminator is successful, there is no reason for Skynet to send him back to the past to kill Sarah Connor. If he doesn't kill Sarah Connor, then she gives birth to John. And now Skynet has a reason. It's a paradox. It doesn't bother me.
But that's NOT the hole I am talking about. What I am talking about happens right smack dab in the middle of the movie.
After being chased at high speed by the Terminator, as well as the police, Sarah slams on the brakes and the Terminator drives straight into a wall. The police catch up, presumably thinking that Reese has kidnapped her and is responsible for the other murders. So they arrest him.
The hole is... where did the Terminator go?
It simply vanished! Hell, that's even the word used in the script: VANISHED.
There is no way a machine that, as we see later in the film, can be shot repeatedly, launched off a motorcycle at 100 mph, run over by a semi truck, set on fire in an explosion, and blown into bits, and STILL chases after Sarah as just a head and a hand would EVER simply walk away without finishing off Sarah.
So why does this obvious gap work, and no one really care? Most people spend more time arguing the semantics of time-travel than this... Why?
I'll go out on a limb and say it is because any other result would have weakened the film. What are the options?
1) The Terminator busts out of the car and attacks Sarah Connor.
This would make the movie much shorter. Either it ends right there. Or you do the whole finale chase... but you lose a lot of exposition that we need, the small love story, the reason why Sarah is being chased. Plus the cops see the whole thing, so you lose that nice piece of tension created by nobody believing them.
2) The Terminator is thrown from the vehicle and has been damaged to the point that it needs to fix itself, before pursuing.
Could happen...? Yes.
But at the expense of this flawless unstoppable killing machine. The Terminator "will never stop." To do anything less, would be to undermine the Thriller aspect of this film and weaken the character of the Terminator, not to mention the threat to Sarah.
So why undermine it?
This scene is where the split genre of the Terminator takes its biggest toll on the believability of the story. It is a SciFi Action Thriller. This means not only does Sarah need to be pursued relentlessly with a bunch of twists and turns to fulfill the genre of Thriller, she needs to be pursued in a manner that can also be called Action. There is no walking out the back door, sleight of hand trickery that will satisfy an Action Thriller junkie at this point in the film. If Sarah is to walk away... stop the chase in the middle of the movie... it needs to be big.
And it is.
My heart still races when I watch that chase sequence and the action buff in me is so satisfied when you see the head on -- CRASH!!! into the concrete wall to end the chase.
The Terminator vanishing? Eh. Who cares? He'll be back. He even tells us so. And you can be sure to bet that the s--- is really going to hit the fan then.
A movie is about the rollercoaster ride of audience expectation and not the perfect flow of logic. That is not to say large gaps can't knock a viewer out of the movie. They can. But if having to make a choice between the two... as is the case in Terminator, go for the rollercoaster ride.