"None of us will really get a true chance to redeem Laurel, because she's gone." Ramsey told ComicBook.com. "But the characters are still reeling from that, particularly Oliver and Diggle."
While Laurel did seem to have returned in the show's midseason premiere, she was revealed to be Laurel's evil Earth-2 doppleganger, Black Siren. In the end of the episode, Oliver Queen (Stephen Amell) decided to keep Black Siren locked in ARGUS custody, with the hope that she will redeem herself and end up being more like Earth-1 Laurel.
Diggle remained inside jail - where his character has been serving time after being framed for crimes committed by a dirty general overseas - for the entirety of the episode. But Ramsey said that the weight of that decision, and the themes of that episode, were felt with his character. ""Oliver clearly was dealing with that with the return of Laurel, aka Black Siren, of just that opportunity of redemption. Diggle didn't get that chance, obviously."
Diggle and Laurel often worked together throughout the course of the show, both as members of Team Arrow and as civilians. Laurel even used her experience with resurrected siblings - her sister Sara has cheated death several times, after all - to help console Diggle when his brother Andy (Eugene Byrd) miraculously returned from the dead as an underling of Damien Darhk.
According to Ramsey, the John/Andy dynamic - particularly John's reluctance to kill his brother - and the subsequent effect it had on Laurel's death, are still sticking with his character in this current season. "He's still reeling from last year. And part of what's going on with him internally is still trying to cope with the choices that he made."
Nevertheless, Ramsey hinted that in this season, Diggle's regret has and will continue to affect his performance on the show. "Even though it's more internal as an actor," he explained, "there's still a certain amount of weight behind those choices."
Arrow airs Wednesday nights at 8 p.m. ET/PT on The CW. A new episode, titled "Bratva," debuts tonight.