Dornan's character Sheriff Graham was murdered by Regina (Lana Parrilla) in Sunday's episode but Dornan told E! Online that he was told about the twist after the pilot was picked up by ABC.
"It was a strange thing because I've seriously bonded with these people," he said. "We're all stuck together for four months and you make proper friendships.
"The weird thing always weighing in the back of my mind was the episode was getting closer and closer. You start trying to adjust accordingly."
However, Dornan hinted that he may film more scenes for the show in the future.
"I'm not sure if this will be the last you'll ever see of my face on the show, but it's certainly the last you'll see of Sheriff Graham," he said.
"[Returning to the fairytale world has] been discussed, definitely. I mean, my fairytale character [the Huntsman] doesn't die, so there's always that option. There's so much that can happen."
Dornan also joked that he was pleased with Graham's death, which happened when Regina squeezed his heart until it was dust.
"It's pretty gruesome, but you know, it's a little bit cool," he said. "Not many people get to die like that. It's a bit cooler than getting shot in the arse or something. So as TV deaths go, I was pretty happy."
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