Without the interference of the undead army, the speed at which Zhou Tian can annex the undead territory has naturally accelerated considerably. In the three days Zhou Tian was unconscious, much of the undead territory he previously occupied has already been absorbed. Thus, Zhou Tian could now at any time transfer a significant portion of the army stationed in his rear, and if we add the military power Zhang San has supplemented for Zhou Tian, Zhou Tian, if daring enough, could even seize the undead territory entirely in one fell swoop.
Without any hesitation, Zhou Tian issued an expeditionary order immediately after regaining consciousness.
The main reason Zhou Tian initially chose to occupy a portion of the opponent's territory and fight a final battle with them was primarily because the main force of the undead army remained intact. Fearing that his rear would be cut off by enemy stealth attacks at any time, Zhou Tian made the strategic decision accordingly.