The black tsunamis engulfed the underground corridor from both ends, trapping most of the Practitioners in the remains in between. With no way to back down, they could only fight till the end.
The Class C's formed the first line of defense with their Spirit Qi armor, which served as effective protection against single bugs. Initially the big organizations wanted to force individual Practitioners to shield off bug floods from the front, but soon they realized that their defense was too weak to sustain without Spirit Qi armor.
If all the individual Practitioners died off, big organizations like themselves, would be no match for so many beetles. They could be easily breached against such a grand scale of monsters.
An analogy would be, how could a powerful man who could defeat ten or a hundred enemies at the same time be able to overpower thousands or more? Besides, there were no Class A's among them.
