By James Hibberd
Updated July 28, 2011 at 08:38 PM EDT

Doctor Who executive producer Steven Moffat reassured fans alarmed by a Comic-Con trailer that suggested an upcoming episode would have the time-traveling doctor helping Adolf Hitler. In the clip from the upcoming midseason premiere, Hitler seemingly thanks the Doctor for saving his life.

“I think we can unequivocally say we’re against Hitler,” Moffat told critics at the Television Critics Association’s press tour about the episode, titled Let’s Kill Hitler. “I think the worst thing you can do to that awful man is take the mickey out of him on Doctor Who. Don’t worry, we’re not going to save Hitler.”

Moffat said he’s in favor of continuing to stretch the boundaries of the show and surprise the audience. “The only way you can keep the show alive is to make changes,” he said.

That includes the show embracing more of a serialized storyline and in addition to its usual stand-alone episodes. “The trouble with a series as it gets older it can feel like a tradition,” Moffat said. “And tradition is the enemy of suspense. It’s about keeping it lively and suspenseful … The story of the week still takes center stage. What we have is a more extremely version of what we’ve always had. All the stories will end and satisfyingly.”

Meanwhile the latest Doctor, Matt Smith, said his favorite Doctor in the show was the second Doc played by Patrick Troughton: “He’s weirdly peculiar without ever asking you to feel he’s weirdly peculiar,” said Smith. As for so many making an issue about Smith being the youngest Doctor yet, he said, “There’s something interesting about having a young face and old soul. It allows you to reinvent feeling old.”