'Red Notice' director talks spoilers, why he won't say who came up with the Vin Diesel joke, and how that surprise cameo was pulled off

• Warning: Major spoilers below for Netflix's "Red Notice."
• Director Rawson Marshall Thurber talked about how that major cameo was pulled off among other details.

Thanks to movies like "Central Intelligence" and "Skyscraper," writer-director Rawson Marshall Thurber has become one of Dwayne Johnson's go-to directors.

It has led to their latest collaboration, "Red Notice," a globe-trotting buddy comedy/heist movie on Netflix starring Johnson, Ryan Reynolds, and Gal Gadot.

Touted as one of the most expensive movies Netflix has ever made (it was originally greenlit at Universal), the movie is filled with explosions and exotic locations as we follow Johnson, an FBI profiler, who has to team up with a thief (Reynolds) to track down some bejeweled golden eggs before another thief (Gadot) does.

Thurber crafts a blockbuster feel with the action, but it's fueled by the comedic banter between Johnson and Reynolds and a twist ending you won't see coming.

Thurber chatted with Insider and answered our burning questions - like how did that surprise cameo happen? Who came up with that Vin Diesel joke? And his thoughts on live guns on set following the fatal shooting on the Alec Baldwin movie, "Rust."

For 2 weeks, shooting took place inside a mine shaft 400 feet underground

In the final big action sequence of the movie, FBI profiler John Hartley (Johnson) and thief Nolan Booth (Reynolds) team up with fellow art thief The Bishop (Gadot) to run from authorities by speeding down a giant mine shaft that's attached to a bunker of buried Nazi treasure.

Though many will think this is just another CGI-manufactured action sequence, Thurber says they really did go deep underground to film it.

"We spent two weeks 400 feet underground in a mine shaft just outside Atlanta shooting that sequence," Thurber said. "Those were long, cold, dark days."

Thurber admits that the shots of the actors in that sequence were done on a soundstage, but the high-speed car chases with stunt doubles were done in the real mine shaft.

"People don't believe you go and do these things because of how great visual effects have gotten," Thurber added. "But I'm really glad we shot that practically. I think it made all the difference."

Did you catch that nod to "Titanic" in the movie? Ryan Reynolds came up with that

You may have noticed that Booth's boat in Bali has a phrase written on the side: "We're going to make it, Rose."

"Titanic" fans will know that's what Leonardo DiCaprio's Jack says to Kate Winslet's Rose right before they go into the icy water after the Titanic sinks.

Thurber said the idea of putting that line on the boat was all Reynolds.

"They were making the boat and my production designer Andy Nicholson asked me, 'Do you want anything written on the side?'" Thurber recalled.

"I think I texted Ryan and was like, 'Hey, man, what do you want on the side of your boat?'" he continued. "And literally three seconds later he texted back, 'We're going to make it, Rose.' I was like perfect, and that was it."

Thurber's favorite line in the movie is an old Alfred Hitchcock term

Thurber loves a good movie reference and there are a bunch in "Red Notice," but his favorite is the offhand remark Booth gives Hartley while they are looking for a box in a massive underground warehouse of Nazi loot.

Hartley asked Booth: "How are we going to find this egg?" To which Booth responds: "I don't know, look for a box that says MacGuffin."

MacGuffin was a term used by Alfred Hitchcock for a thing in his stories that the characters are focused on but is insignificant to the audience. Like the cash that Janet Leigh's character steals at the beginning of "Psycho" that leads her to the Bates Motel. Characters throughout the movie wonder where the money is, but all we care about is that she died in that shower at the hands of some maniac.

For "Red Notice," the main characters are looking for jeweled eggs. But all we the viewers really care about is the adventure they are going on.

"Ryan's MacGuffin line makes me laugh every time," said Thurber, who confirmed that he wrote the line.

"Some of these jokes are just for me," he added. "They work for me."

Thurber believes real guns should still be used on movie sets following the fatal death on "Rust"

In the wake of Halyna Hutchins' death on the Alec Baldwin movie "Rust," many filmmakers and industry bodies have been calling for heightened gun safety on movie sets. Some are even pushing for an end to using real guns altogether, arguing that all the effects should be done in post-production.

Johnson is among those to have vowed to stop using live guns in their movies.

Thurber has used guns in many of his movies, and "Red Notice" is no different.

"We used replicas and put in the muzzle flash and the sound later [in post production], we used air-soft replicas that are not real firearms but they cycle and move like a real one, and sometimes we would use quarter-load or half-load blanks," Thurber explained.

"I do think there is value using blanks on set," he continued. "Both from a performance and photographic standpoint. I think actors perform differently when there's sound and light coming from the weapon."

That said, though, Thurber believes new steps have to be taken if you want to use working firearms on a movie set.

"I think we need to take a hard look at our procedures and our precautions," he said. "Maybe there's a way to make the baseline be replica weapons and if you need or want live firearms on set that there's a special waiver or special approvals that have to be handled."

Thurber won't say who came up with the Vin Diesel joke

"Red Notice" is filled with one-liners delivered by Reynolds, but the zaniest is at the end of the movie when Hartley says to Reynolds' character: "You know what I think is funny, Booth?" And Reynolds responds: "Vin Diesel's audition tape for 'Cats?' It exists."

Thurber would not come clean on who was responsible for it.

"I'll never tell," Thurber said with a laugh. "I plead the fifth, it was a team effort."

The beef between "Fast and Furious" costars Johnson and Diesel has been well documented, however, the Rock has already come forward to say that joke in the movie didn't come from him.

"It's interesting, these Vin Diesel jokes - which play great, by the way, to the audience, which is always a good thing, because it's really all about them - but people think these jokes come from me and they actually don't," he said on SiriusXM's "The Jess Cagle Show."

The Ed Sheeran cameo was the final scene shot in the movie and was done during the pandemic

Following the big twist reveal that Hartley and The Bishop were working together all along, we find the two at a swanky wedding where Ed Sheeran is performing his song, "Perfect."

Thurber said Sheeran being the movie's surprise cameo was always his plan.

"It was so much Ed that his name was in my notebook when I was scratching out all the ideas for 'Red Notice,'" Thurber said.

"I was put in touch with Ed by a mutual friend and I emailed him and asked if he would do this," he continued. "I sent him a picture of my notebook with his name in it. He's the most delightful human being on the planet and he said he was in. 'The weirder the better,' he told me. And I said, 'That's my guy.'"

But it was a logistical nightmare to shoot Sheeran for the movie, Thurber said, because of rules around live performances in the middle of the pandemic.

"His scene was the very last thing we shot for the movie," Thurber said.

"Because he sings in the scene, we had to be a certain distance away, so we had to have a remote-operated camera shoot him," he said. "It made everything incredibly tricky to achieve. But he was a real trooper. It is one of my favorite moments in the film."

Thurber reveals what could happen in a sequel

The final shot of "Red Notice" is a big tease for a sequel. Though Thurber would not confirm plans for a sequel, he admits he's been thinking of how to do it since shooting began.

"My brain was ticking away figuring out the puzzle of what I would do next," he said. "I just really love the world and the tone and characters so much that I can't help myself but think about what the next heist would be. It's certainly something that could happen."

A sequel idea we threw at Thurber was the possibility of seeing Hartley's father, who he explains in the movie is also a con artist.

"That's not half bad and if I'm being honest it's something that's crossed my mind more than once," Thurber admitted.