Living underwater means lungs are filled with fluids, which is why Atlanteans will spew it out like vomit when they are suddenly out of water in Aquaman.
While visiting the edit bay of Aquaman with director James Wan, ComicBook.com saw a trio of scenes from the upcoming DC Comics film. Following one sequence which pitted Orm against Arthur, Mera is forced to rescue Aquaman from the battle by opening a patch of air underwater. When Orm lands inside of it, he struggles to gather himself, briefly flopping (ironically, somewhat like a fish) and ejecting a fountain of water from his mouth.
As it turns out, there is a good bit of logic and science behind the move which sees Orm emptying his lungs.
"Just from a practical standpoint, people ask me, when they talk, 'Is it bubbles that come out of their mouth?'" Wan explained. "No, 'cause there's no air in your lungs, so there wouldn't be any bubbles, right? Because you don't do that, right? And, so, then, in that sequence, where you saw Mera open up this air pocket to suck Orm away from Arthur, help him out, now, when he's breathing, the first thing he does is he using the air pockets, where he could get out all of the water that's in his lungs."
Meanwhile, none of Aquaman's cast member were forced to endure underwater filming sequences. Although the characters zip through water and have their hair and clothing appearing to be floating through their surrounding element, the entire film was shot using a "dry for wet" process.
"It is very difficult just trying to simulate that, the look of weightlessness that you would get under water, but we did tons of R&D very early on," Wan explained. "With how people would move under water. We built props, we built sets, and we submerged everything under water, and we did tons of study just to see what things would look like. Ultimately, what we realize, is what we can do under water... We're still very much limited by what we're capable of doing, because we're normal human beings. We're not Atlantean, right? These guys, obviously, move very differently in a water space, in that space. To them, they're basically like super heroes, but, for us, we swim slowly."
Aquaman is set for release on December 21, 2018.