The Atlantean Neptunium was special and its unique properties allowed it several things like making a barrier that prevented cultivators from getting in, but it also had its own limitations.
One such limitation was that its stability was only maintained in water. It could certainly be taken out of water if it was kept inactive, but if its effects were still being used it could explode with a devastating power.
The energy contained within the statues was no joke as they were entirely made out of Atlantean Neptunium.
"The amount of Atlantean Neptunium they have here is massive. They wouldn't need this much to protect a city of this size, even a quarter of it would have been more than enough. They have intentionally added more as they wished for not only it to be destroyed but anyone and anything that might be in its periphery in case of emergency." Xukong said after assessing the situation.