Undead Scourge (3)
If not for Samiel's continuous usage of the Winter Ruler to create and frost waves across the entire city, which caused the city to start freezing up, then at least one-third of the buildings would be already set on fire by the Undead Scourge that tore its way from the main gate to the plaza.
This was another advantage of Samiel slowly freezing the entire city to one huge chunk of ice was that, once the city caught on fire, it would be like giving a signal to everyone in the surrounding cities that something was happening, which would cause them all to be on alert, meaning it would be more complicated for the Undead Scourge just to slaughter their way through.
Samiel wanted to kill as many people as possible and if the news spread too fast that something was happening here, he won't be able to harvest so many souls. And amidst all of that chaos, Samiel was just observing and observing everything, slightly thinking about the greater insignificance of life.