The final sequence in the Master's headquarters was intended to contain the giant Ogron-eating monster, but director Paul Bernard did not like the costume and omitted it, leaving the scene with just frightened Ogrons running away from something unseen. Producer Barry Letts and script editor Terrance Dicks felt the sequence lacked impact and a new ending was filmed in the TARDIS as part of the first production block of the following story, "Planet of the Daleks". "Frontier in Space" was Paul Bernard's last "Doctor Who" work.