Zhou Tian, despite his wariness of those NPCs, was already too far along to stop his actions now. In that moment, he had firmly decided to fight those NPCs and had even made strategic preparations to confront them.
As for the combat, it need not be mentioned. Although the NPCs might have some hidden trump cards, Zhou Tian believed that based on their performance, they did not have the confidence to defeat him. Zhou Tian had already taken action personally, and if he could not defeat those NPCs himself, then he had no other methods to use. With his personal engagement, the battle was essentially him exerting his full strength.
In other aspects, Zhou Tian had also made some arrangements.
For instance, if those NPCs wanted to send their kind off to other continents to pass on their civilization, that would certainly not be an easy task.