James Cameron Admits 'Jack Might've Lived' If He Shared Door in 'Titanic' : But There's 'Variables'

James Cameron is giving fans an inside look at how the last few moments of Jack and Rose's romance could have gone following the sinking of the titular ship in Titanic.

The 1997 film's director commissioned a scientific study to determine if there really was enough room for both Jack and Rose DeWitt Bukater (played by Leonardo DiCaprio and Kate Winslet, respectively) to fit on the ever-debated floating door after the Titanic sank in the Oscar-winning blockbuster.

A first-look into the National Geographic special about the study, Titanic: 25 Years Later with James Cameron, premiered on Good Morning America Tuesday.

To find out — once and for all — whether Jack could have survived had he joined Rose on the floating piece of debris, Cameron and a team of scientists hired two stunt doubles to reenact four different scenarios.

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At one point in the clip, both Jack and Rose are halfway on the piece of debris, but their lower halves are completely submerged in the freezing water, so it's likely neither would have survived in that position. In another position, they are both seated on the debris, and Jack is shaking violently from the cold. "He could've made it pretty long, like hours," Cameron said of the seated position.

It's only once they test the scenario when the two stunt people are as exhausted as they would've been in the real situation — like the moment where Rose is shoved underwater by another survivor before Jack swims over and punches her attacker. Once they both are seated on the floating debris, Rose offers Jack her life jacket, and he "stabilized."

"She got him to a place where, if we projected that out, he just might have made it until the lifeboat got there," Cameron said.

In the end, the film's writer-director seems satisfied with the conclusion that there will never really be a clear-cut answer to the question, but regardless, Jack acted out of pure love.

"Jack might've lived, but there's a lot of variables," Cameron said. "I think his thought process was, 'I'm not gonna do one thing that jeopardizes her.'"

In an interview with Postmedia ahead of the National Geographic special announcement, Cameron said that Jack "needed to die."

"It's like Romeo and Juliet. It's a movie about love and sacrifice and mortality. The love is measured by the sacrifice."

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The special coincides with the 4K restoration of Titanic, which opens in theaters Feb. 10 to celebrate the Academy Award winner's 25th anniversary,

PEOPLE is celebrating the film on its 25th anniversary with a new Titanic special edition, which includes a behind-the-scenes look at its making and legacy. In the issue, Cameron opened up about reuniting with Winslet for Avatar: The Way of Water, as well as his ongoing obsession with the RMS Titanic.

"Yeah, I was a little bit obsessed there for a while," the director and writer told PEOPLE, adding, "I'm not going back out to the wreck. I've done my investigation. We are putting all our data together with some of the other experts . . . to do a definitive publication on the marine forensics of the wreck."

Titanic: 25 Years Later with James Cameron premieres Sunday, Feb. 5, at 9 p.m. ET on National Geographic.