'Star Trek: Discovery's' Anthony Rapp on 'Mind-Altering' Twist and Stamets' Love Life (Exclusive)

CBS All Access

Warning: Spoiler alert! Do not proceed if you have not watched Sunday’s episode of CBS All AccessStar Trek: Discovery.

Sacrifices don’t come without consequences.

On the latest episode of Star Trek: Discovery, released Sunday on CBS All Access, one member of the USS Discovery crew made a critical decision that saved the starship fleet, including its imprisoned captain (who's sharing a cell with Rainn Wilson's Harvey Mudd), from imminent disaster. 

Lieutenant Paul Stamets (Anthony Rapp), scientific mastermind, reluctantly teams up with mutineer Michael Burnham (Sonequa Martin-Green) to figure out a dangerous alternative to make a necessary long jump without relying on the Tardigrade (aka the Ripper), which locks into survival mode after its last painful trip to the reaction cube. Stamets, it’s revealed, injects himself with the spore technology, saving Captain Lorca (Jason Isaacs), the Discovery crew and the Ripper. But the unknown consequences of Stamets’ decision is a mystery that will unravel over the course of the season.

RELATED: 'Star Trek: Discovery's' Jason Isaacs on Captain Lorca’s Debut and Shatner Tribute

"You get a little glimpse in the scene in the bathroom,” Rapp tells ET of the final scene, wherein Stamets’ demeanor -- previously seen as a prickly, sarcastic, no-nonsense science guy -- seemingly switches on a dime with a telling wry smile in the bathroom mirror. Clearly, something’s changed with the astromycologist. 

“His whole life he’s been looking, trying to understand something and he experiences it firsthand. It’s overwhelming. That, in itself, is profoundly mind-altering and mind-opening and fulfilling and consuming,” the former Rent star explains. “It has other kinds of ripple effects. It opens up new doors and the way that it develops is really compelling. Nothing about any of this to me is typically predictable. It touches on things that are constantly surprising.”

Though Rapp was coy about specifics in regards to what awaits this “new” Stamets, he promises Trekkies that answers are doled out “in pieces” -- just don’t take all of it at face value. 

“Some of the pieces seem like they’re going to be one sort of thing, but they’re another thing and vice versa,” he hints. “One of the things about serialized storytelling is that you plant seeds that bear fruit two, three, four, five episodes down the road. Everything does bear fruit.”

RELATED: ‘Star Trek: Discovery' Star on Premiere Cliffhanger & How It Affects the Future

CBS All Access

Stamets’ life away from his professional duties was explored for the first time in Sunday’s episode, his relationship with Dr. Hugh Culber (Wilson Cruz) coming to light in a sweet conversation between the Starfleet colleagues. Rapp zeroed in on a piece of dialogue by Culber -- “You don’t care about you, but I do” -- as proof positive that the couple, the first openly gay pairing in Star Trek TV lore, works on many different levels.

“Like many scientists, he’s obsessed with his work and probably spends hours in front of whatever experiment or investigation [he’s been tasked to work on], and doesn’t remember to eat, doesn’t remember to go to the bathroom, doesn’t take a shower. That’s pretty typical of probably many driven scientists and I think they ground each other in different ways,” Rapp says, before adding with a laugh, “Well, Culber certainly grounds Stamets. I’m not sure Wilson would say Stamets grounds Culber. They balance each other.”

Rapp says it’s been “deeply important” to be one-half of the first openly gay couple in a Star Trek TV series. Star Trek: Discovery, for its part, doesn’t make a big deal over the history-making moment, instead treating Stamets and Culber like any other romantic coupling.

“For whatever reason, it took this long,” Rapp says. “But it was also important that it be completely part of the fabric of the story. It’s also smart of the writers and meaningful that you see them in the midst of their relationship, that they are already a mature, settled partnership living and working together -- that you get a glimpse of that in a way that’s unusual for Star Trek, in an intimate, very domestic moment like this. I’m proud that it’s so simple and direct.”

Star Trek: Discovery premieres new episodes every Sunday after 8:30 p.m. ET/5:30 p.m. PT on CBS All Access. The After Trek aftershow launches live Sundays at 9:30 p.m. ET/6:30 p.m. PT.