But then it could be argued that unlike normal circumstances where the Doctor announces his displeasure at such an act and then departs, he's having to learn to live with it. He can't do his usual tactic of legging it, and like a normal person he is forced to interact with The Brigadier due to their job. That he then discovers that The Brig isn't the monster that one act made it seem, but the same person he came to respect. Yes, he did commit the act of atrocity against the Silurians, and it is something to keep in mind, but it doesn't change the character completely.
Though I got the distinct impression later on, as the Doctor strives for peace, that the Brigadier gives him a bit more latitude than he has done in previous stories in an attempt to win the Doctor back over. But I feel that's me projecting onto the material in a way the writer never probably foresaw.
But looking beyond the legacy of the preceding serial, The Ambassadors of Death might just be one of the perfect examples of how to do Doctor Who stuck on Earth. The serial is tense, and heavily espionage tinged with the conspiracies a plenty, double crosses, and a vague alien threat offering a boiler plate for all these human emotions to play out. And doing a more believable job than The Silurians where a couple of characters were slightly OTT or just plain stupid for the sole reason of Plot.
It's not perfect by any means though. There's the small matter of the space centre having the laxest security ever, especially when it's being overseen by UNIT in these special circumstances. Letting the same saboteur onto the grounds on two separate occasions, in a baker's van of all things, and just run around while very important tasks are being carried out, like launching a space rocket is laughable. Once was a concession you can make, but the second is just taking the piss and risks pushing the entire thing into the realm of farce.
However, on the flip side of that is The Ambassadors of Death's trump card. Here the aliens aren't evil, just incompatible with humans. In fact they are actually Ambassadors, just like the title suggests. Unfortunately they give off huge amounts of radiation killing any human they come into contact with. Oh, and can be controlled via radio signals. So it's understandable how they seem to be classic Doctor Who monsters, they have all the hallmarks, but it's not their own doing.
The real badguy is a military general, Carrington, who wants war. It could come across as a cliché, but here it really doesn't. The writer gives him the decent motivation of the aliens killed all of his crew during a Mars mission, and he can't see beyond that. It's not just generic military bravado of shooting the unknown, but shooting the very known that had already caused him great harm. OK, so he can't see past his nose and realise it was a mistake. That is where the cliché vaguely shows it's face, and because of the death of his men he's convinced the only way to deal with these aliens is to trick everyone else on Earth that they're violent so he can get the Government's blessing to wipe them out, and be prepared for future alien invasions. It's a great accomplishment that the writer actually made the cliché war-hungry general relatable.
Then there's Reegan, a proper criminal who is meant to be working for Carrington. But he sees other potential than just starting a war, and since he has total control of these radioactive aliens realises he can use them for personal gain. There's a rather dark episode with Reegan killing minions off when he no longer has a use for them, even rather prominent ones, and just dumping their bodies at a quarry and burying them under a ton of gravel. The fact that he's insanely ruthless and murders anyone who is now a burden makes him one of Doctor Who's most scary monsters ever.
One of the things I remember most about The Daemons was the over-reliance on a synthesiser for the backing music. It stood out a mile, but at least it fit. The music in The Ambassadors of Death sticks out a mile as mostly being completely out of sync with what's going on onscreen. The otherworldly and mysterious music for the Ambassadors is perfect, but it's used whenever they're onscreen, even after we've had a complete explanation of who they are and how they're being used. It just sucks you right out of the moment.
Oh and that bit where Doctor goes into space is a bit dodgy, but that's the only time I felt the show was going too far, and the conversation with the alien mothership was needed, I just wish it could have been done a better way.
On the back of The Silurians and Spearhead from Space, this different era of Doctor Who is proving itself. I'll admit to it being a little odd that we're still on Earth, and I wouldn't mind the Doctor go somewhere else even for one story, but we've had three compelling arguments as to why being stuck on Earth is an interesting premise.