Darkling random thought (spoiler-ish)
I can't shake off the feeling that, if the Darkling had been younger at the time of using the Fold as a weapon, he'd have done things differently.
Let me explain. Firstly, using the Fold as a weapon is a good idea. Strategically speaking. And in a war, what is strategy if not the foundation of survival?
Secondly, Aleksander loves Ravka. He could have flee, keep hiding, start a war on otkazast'ya (hopefully i spelled it right) ages before and turn the tables around. But he doesn't care just for Grisha. He cares about ravkans, all of them.
Years of suffering and futile attempts to have his dream of peace and happiness fulfilled, however, made him prone to drastic measures. Had he been younger, that hopeful boy/young man from early life, I'm sure he would have cleaned the town of civilians. He didn't want to kill those people: in the books he needed to show off to those messangers from Shu and Fjerda and Kerch etc..., in the show, his only target was Zlatan (not sure of the name, the separatist leader) and his suppoerters.
But since immortality clearly took a tool on him, his thoughts would follow the "what is one more sacrifice in the long run" line. He already lost so much, so much has been taken from him, he did so many gruesome things to survive/for the cause, what is one more? One more, to lead to that peace he's holding onto for dear life.