If he didn't do something soon, the ball of Void Qi would reach the Realm Fracture, and then, not only would Mu Di Bai's formation and presumable formation be wasted, but the world on the other side, although not innocent, would be returned to Chaos for no reason.
Although Di Tou had made up his mind to act, that was the most desperate situation! Like a president in front of a bunch of nuclear launch codes, if he thought that his country was coming to an end and there was no resolution, perhaps he might send out the order, but if he were to find out it was all a false alarm, naturally he would swiftly and expediently cancel the order in hopes that it was not too late.