The penultimate episode of season two of Dark Matter premiered Friday on Apple TV. Based on the New York Times bestseller by Blake Crouch, the series is about the possible ways your life might have been different if you made different choices, and how the choices you choose to make shape the person you become. In season one, physicist Jason Dessen (Joel Edgerton) was abducted and dropped into an alternate version of his life by another version of himself. After making his way through a myriad of different realities via the Box, he eventually makes his way back to his own universe and his family.

The alternate version of Jason did not only kidnap another Jason, however, but also his friend Ryan (Jimmi Simpson) from the same universe. In season two, Ryan joins forces with Amanda (Alice Braga) as they travel through different realities, searching for a cure to a deadly virus they encountered along the way. In the ninth episode of the season, the two arrive in World X, where Ryan and Amanda are finally reunited with Jason. Their reunion also brings them together with Blair (Amanda Brugel), who proposes a way to shut down the Boxes permanently, potentially putting an end to travel between realities.

Simpson recently spoke with SciFi Vision about playing multiple versions of Ryan in the series, including scenes in which the characters interact with one another. He discussed the technical process of working with stand-ins, the differences between the Ryans’ emotional and intellectual strengths, and why the low-tech environment of World X appeals to him personally.

The season finale of Dark Matter premieres October 30th on Apple TV.

Watch the full interview below.