Dr. Who was at its most mature in the 1980s.
Sci-fi was "safe" up until the late 1970s. You had the laser surgury sequence in Logan's run--amputations by heroes in Star Wars--
and then came ALIEN, and The Thing.
So when Star Trek II came along, post John Carpenter (Halloween) there was a sense of danger.
Earthshock was part of this era. I think Tom Baker faced an alien that fell on a vial of diseased material and the back of its head turned to jelly--but Dr. Who was around its most violent in the 5th sixth Doctor era.
Davros got shot in the palm--and perhaps most chillingly, Lytton gets his hands crushed by Cybermen:
That shocked me even as an adult.