In a new interview with TVGuide.com, Mary McDonnell talks about the unlikely path that took her from guest-star to series lead, and Captain Raydor’s transition from foe to friend of the squad.

“I’ve never had something grow this way,” McDonnell tells TVGuide.com. “This was just a delightful three-episode romp, and I was very excited to be able to fully embrace the antagonist. Then it just grew and grew. And I was standing by going, ‘Well, this is interesting. Let’s take another step.’ I don’t think it was really until we [premiered] a few of weeks ago that it truly occurred to me what had happened.”

Read the whole interview here.