Gawain and Scaroth

Transcribing notes from the course on the Arthurian legends that I'm finally taking, decades after it was an undergraduate option that I never quite managed, and today's lecture was mostly on Sir Gawain and the Green Knight. And one of the notes, as one of the questions Sir Gawain apparently poses is whether Arthur's court was as ripe for falling as Troy had been before it, ran

The death of a civilization is also the birthplace of a next one.

Which in the back of my mind spawned a City of Death cross-reference (because of course it did) (full transcript):

DOCTOR: No, Scaroth, no. You've pressed it once. You've thrown the dice once. You don't get a second throw.
SCAROTH: But I will splinter in time again, and all my people will be killed!
DOCTOR: No! The explosion that you in there are about to trigger off will give birth to the human race. The moment your race kills itself, another is born. That has happened. It will happen.
SCAROTH: What do I care of the human race? Scum! The tools of my salvation.
DOCTOR: No, the product of your destruction. History cannot change. It cannot!
SCAROTH: I will change it!
(So Duggan punches his lights out.)

(As Duggan himself noted at an earlier point in the story, “Well, what else would you suggest?”)