The troop development in Thunderhawk City had always been based on a policy of elite soldiers. The number of troops under Rocky's command might not be many, but from all aspects, they could be considered elite. However, don't forget, in the battle against Demons, even the most elite troops couldn't withstand the seemingly endless number of demons.
Therefore, based on Rocky's experience, it would be difficult to defend Thunderhawk City with just the existing troops. This made him furrow his brow and prevented him from making a rash decision. Instead, he had Monte and others discuss first, asking them to come up with a defensive plan before considering what to do next.
Fortunately, although the mission was daunting, time was on Rocky's side. He could wait until he was fully prepared before choosing to lower Thunderhawk City to the land. Of course, considering his current situation and the overall state of the world, there wasn't much time for preparation.