After David Tennant had his first Doctor Who adventure in “The Christmas Invasion,” the season two premiere episode “New Earth” gave us a proper introduction to this new Doctor and his unique way of handling problems. One of these problems is a big one: in the New Earth of the far, far future, the Doctor and Rose encounter artificial humans who have been infected with a series of horrific diseases. Originally, this episode would have had the Doctor killing them all, and it was only changed because showrunner Russell T. Davies was jokingly chastised by future showrunner Steven Moffat.

New Earth Was Toned Down

To appreciate this hilariously bonkers Doctor Who story, you need to understand a bit more about the “New Earth” episode. It begins with the Doctor and Rose encountering feline nuns in New New York who are tasked with curing various diseases humanity faces. That works well on paper, but it turns out that their method of developing cures is to infect artificial humans with every disease in the known galaxy.

Save Everyone

That sounds cruel and unusual even by Doctor Who standards, but “New Earth” makes it clear that the feline nuns are doing this in order to cure the diseases of the various people who keep coming to settle the planet. Things eventually go sideways when some of the artificial humans are released and become the equivalent of an attacking zombie horde. In typical fashion, the Doctor is able to whip up an antidote that saves everyone and shows mercy to his mindless enemies.

Russell T. Davies Was A Bloodthristy Writer

We think of this merciful gesture as something commonplace on Doctor Who, but that wasn’t exactly the case when “New Earth” was first written. Showrunner Russell T. Davies penned this episode, and as longtime fans know, he’s not afraid to take his characters to some dark places. In this particular case, he was quite bloodthirsty: not only was Davies going to kill the fascinating new character known as the Face of Boe, but he was going to force the Doctor to kill the infected horde.

One Note From Steven Moffat

What changed the Doctor Who showrunner’s mind so that we ended up with this much more mellow final version of “New Earth?” It began when he picked up his own copy of The Shooting Scripts, an official compilation of the scripts used for the first season’s production. In this episode, series writer and future showrunner Steven Moffat left a joking note about Davies: that the man “creates interesting characters and then melts them.”

Obviously, Davies wasn’t all that hurt by the observation, but he did end up taking Moffat’s words to heart. Because of them, he changed the script so that the Doctor was able to save both the Face of Boe and the artificial humans trying to kill him. While Davies didn’t explicitly speak on this matter, it seems clear that Moffat’s words would continue to affect him, which is likely one reason why Tennant proved to be a kinder, gentler Doctor than Christopher Eccleston.

Latest Season Keeps The Save Everyone Ethos Going

It’s quite possible that the influence of Moffat’s words on Davies is still being felt: Doctor Who has come a long way from “New Earth,” but the latest season has revealed a new Doctor (Ncuti Gatwa) who would risk his own life rather than consign a monster to the vacuum of space. The character is all about empathy and respect for all life. And that might not be the case if another showrunner hadn’t called Davies out for his frequent tendency to melt his best characters.