I quite like also that the Third Doctor isn't all "you humans are about to bring destruction upon yourselves through your own stupidity" from the start. While he baits Stahlmann, it's fairly clear Stahlmann has that effect on a lot of people, so the Doctor is really just there for his own experiments. I mean, I think that contributes to the rather muddy environmental messaging, but it's also nice from the perspective of the Doctor's character.