'Terminator: Dark Fate' director describes his big argument with James Cameron about time travel

• "Terminator: Dark Fate" director Tim Miller told Business Insider he had a disagreement with James Cameron on a time-travel element.
• Cameron wanted the movie to look at the first time a Terminator went back in time to kill its target, while Miller felt it wouldn't work.
• Miller eventually won out, as some of the plot points just wouldn't have made sense if they went the way in the story Cameron wanted to.
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Warning: Spoilers below if you haven't seen "Terminator: Dark Fate."

There's no question that Tim Miller is happy he had James Cameron by his side while making "Terminator: Dark Fate." Cameron, who created the beloved franchise, addressed any question Miller had and helped in tough negotiations, like getting Linda Hamilton to agree to return to the franchise as Sarah Connor for the first time since "Terminator 2: Judgement Day."

But that doesn't mean Miller and Cameron always saw eye-to-eye.

Miller told Business Insider that one of the biggest disagreements between the two was about a time-travel element in the movie.

Like in the first "Terminator" movie Cameron made back in 1984, in "Dark Fate" an unstoppable killing machine goes back in time with a mission to kill someone who brings hope to the future. That person is Dani Ramos (played by Natalia Reyes), who we learn is the leader of the resistance in the future.

"The biggest discussion with Jim was at some point there has to be a first time that someone comes from the future," Miller told Business Insider. "Is Dani a natural in this movie? Is everything that's happening to her happening for the first time?"

Miller said Cameron was very much in the camp of having "Dark Fate" showcase the first time a Terminator shows up to try to take out Dani. However, Miller was not on board.

"I immediately knew we couldn't do it," he said. "Jim really wanted to try to do that and eventually he came around. It wouldn't have worked."

Miller said a big reason for that was because there were certain plot points in the movie that only worked if this was not the first time past Dani's life was turned upside down.

For instance, Grace (Mackenzie Davis), the cyborg soldier from the future who goes back in time to protect Dani from the Terminator, has exact coordinates tattooed on her body of where she has to take Dani (turns out those coordinates lead her to the last T-800 model in existence, played by Arnold Schwarzenegger).

"Future Dani wouldn't know all of that stuff if this was the first time," Miller said.

Miller did say, however, there was something he and Cameron were very much in sync about: keeping the time-travel element as simple to understand as possible.

"I don't believe the audience wants to hear a lot of exposition and theoretical talk about time travel," he said.