By Sandra Gonzalez
April 24, 2014 at 02:24 PM EDT
Diyah Pera/The CW

Even after the Arrow writers made the tough choice to [Spoiler Alert times a billion] kill off Queen family matriarch Moira Queen (Susanna Thompson) in the episode that aired Wednesday night, there was still one more detail to hash out: How would Slade Wilson end Mama Queen’s life?

They knew the scenario — Slade (Manu Bennett) was going to eerily re-stage the tragic death of his beloved Shadow and, in a full circle moment, force Oliver (Stephen Amell) to pick his mother or his sister. (Ultimately, Moira would take that decision out of her son’s hands.) But the actual act of killing came down to one question: sword or a gun? And that decision came with more discussion than you might imagine.

“There was actually a lot of interesting debate among us as writers as well as with the cast and the studio about what was more violent,” executive producer Marc Guggenheim says. “We were all sort of discovering our own proclivities. There were some people who felt like a sword was too violent and there were other people who felt like a gunshot was too violent. And there was very little consensus about what was a better or worse way to go, which I wouldn’t have expected.”

Ultimately, he says, they didn’t “want the brutality of it to overtake the story,” and thought a sword had “more honor to it, in some ways.” “It felt so cold,” he says of the gun option. “It’s a less ignoble death for Moira to die at the hands of a sword than just a gunshot. [The alternative] felt too brutal.”

It was “incredibly sad” to see Moira go, Guggenheim adds: “For one thing, it was sad to see the character go, we loved the character. But it was also sad to see Susanna go.” But if anything, the dramatic farewell also stands as an example of Thompson’s exceptional talent, as Guggenheim points out that arguably the most heart-wrenching line in Thompson’s final scene — when she looked to her daughter (Willa Holland) and told her to “close her eyes” — was entirely improvised.

“Wasn’t in the script,” Guggenheim says. “[That was] Susanna’s idea on the day. It gutted me. I flew up [to Vancouver, where the show films] just for that one scene, and that was something that Susanna, as we were rehearsing that scene, had the instinct to do. I loved it so much.”

For Guggenheim, it was a perfect note to cap off a character who had her share of moral flaws. “The reason it’s powerful, at least to me, is that it shows, even in the moment of her death, she’s thinking about her daughter.”

Speaking of Moira’s children, Arrow‘s next few episodes will show just how “this event basically sets up all the stuff we’d always planned on doing with Oliver and it sets up all the stuff we always planned on doing with Thea.”

“The justification for doing this big thing really lied in it got us to all the story places we had wanted to go,” Guggenheim says. “We don’t always know how we’re going to get there, but we do know the destination.”