Warning: The following contains major spoilers for Stranger Things 3.

In the final moments of Stranger Things 3, the unthinkable happened.

With the fate of Hawkins at stake, Chief Hopper and Joyce Byers — known to many shippers simply as "Jopper" — entered the secret Russian facility under Starcourt Mall in hopes of once again sealing the metaphysical gate linking Earth to the Upside Down.

At first, all seemed fine.

The pair descended into the chasm of enemy territory surprisingly optimistic, an apparent side effect of successfully saving the planet twice before. Donning Soviet military disguises and some particularly glib banter, Jopper began their fight to the finish as a continuation of their season-long buddy cop film-turned-meet cute.

"It all leads to that epic, climactic moment of just one simple look between them."

During a few minutes of reprieve from the action, the burgeoning couple even planned a first date, noting that they "deserved to celebrate" after what would undoubtedly be yet another victorious mission.

Upon first viewing, this exchange appears as a fleeting thought, just some tension-cutting comedy doubling as the overdue verbalization of the duo's unspoken romantic attraction. You know, two birds with one stone.

But minutes later, with a heart-wrenching glance and the twist of a key, the touching moment was revealed to be the last Joyce and Hopper would ever share. In the wrong place at the exact wrong time, Hopper seemed to die in the explosion caused by Joyce in an effort to stop the Russians' Upside Down-accessing technology, and once again shut the gate.

Sitting down with Mashable prior to the release of Season 3, David Harbour and Winona Ryder couldn't divulge much of what they thought about their characters' fates in the shocking finale. However, it was clear that the close friends were in as much mourning then as fans are likely to be experiencing now.

"Well, [the whole season] leads to that epic, climactic moment of just one simple look between them," Harbour says of the absolutely crushing, non-verbal exchange. "To me, that alone [tells] a lot about their shared 30 years of history together."

"I was really happy just to get to spend more time with David," sighs Ryder, warmly glancing at her now seemingly defunct scene partner. "It was really great to have so much with just David and I."

David Harbour as Chief Hopper in Season 2 of 'Stranger Things'. Image: Jackson Lee Davis/Netflix

As Ryder points out, Season 3 provides viewers with a "much deeper glimpse" into the Jopper dynamic — examining not only the things that might have made their coupling work, but also the realities that would have likely made their happy ending impossible regardless of Hopper's untimely demise.

"They have their own traumas, they have their own difficulties, and they do act out on each other," explains Harbour. "I mean, Hopper certainly acts out all over the place. He's constantly angry and doesn't know how to process his emotions."

"There is this thing that they're both very afraid of for different reasons," notes Ryder, emphasizing the strong aversion to commitment shared by both Joyce and Hopper — traits that stem in large part from their respective losses of a partner and child prior to Season 3.

"It's their own brand of dysfunction," Harbour continues. "When you root for Jopper, you don't expect for them to just fall into each other's arms. I think the fun that we bring to it is that it is complicated."

Winona Ryder as Joyce Byers in 'Stranger Things' Season 1. Image: netflix

With Stranger Things 3 all-sewn up and a fourth installment not yet in production, it will likely be years before we know whether that ominous post-credits scene, referencing an unseen American being held in a Russian detention center, reveals Hopper to be alive.

Will Hopper return from his implied death to reunite with Joyce and Eleven and wherever they moved to? Or does Harbour's journey on Stranger Things really end here?

We can't say for sure, but it appears we weren't the only ones left guessing.

"I just, I wonder what would have happened if... you know?" Ryder wonders aloud of the Jopper possibilities never explored.

"Yeah, I know," adds Harbour with a sad smile. "Me too."

Stranger Things 3 is now streaming on Netflix.