RUSSELL As audience members, we have this peripheral, small sliver of hope. We have the knowledge that communism doesn’t win, and the Berlin Wall does come down. And the hope in the back of your mind is that those few hard years will happen, and then they’ll be able to go back and find their kids. They’ll start a slow rebuilding. That’s the only thing I have to hang on to.

There were a lot of difficult moments, but the most heartbreaking is when they see Paige on the platform. Was that a difficult scene to pull off?

RUSSELL It’s everything I love in a story. Our job is such a circus life. We’re always leaving or going or working somewhere far away. There’s something really emotional, always, about a moving vehicle — a train leaving or a car driving away. It adds something. So that train pulling away from the child is devastating to me. Also the way Paige looks — she’s not sobbing. She’s just looking at us like, “I’m not going.” It’s devastating to me. Especially after the loss of Henry.

Was it technically difficult, filming that on the train?

RUSSELL The actual shooting that day was tricky. Obviously we were working with a real train, and it takes a million people to start the train, to get the train moving, then to get all those people in the shot. We were shooting on a Sunday. We had so many extras. We had to have extra crew because of that. So there were a lot of factors that were a little distracting, and made it not so easy. You kind of had to just show up and do your best in a couple of takes.

RHYS I felt enormous pressure. The train was moving away, and we only had one shot of it linking us and Paige. So I do tend to get a little pressured in those moments about getting it right. It’s kind of the worst thing, because then you overthink something. When you know you can have a second take and you can keep rolling, you’re far more relaxed and you can try it a couple of different ways. When they go, “Sorry, we’re only going to get one shot,” you go, “But it’s such an enormous moment!”

This season, was it hard sometimes to understand where your characters were coming from? Some really brutal things went down, even more than usual.