If you want to continue to expand the passage, then the time required is also very long, and there is no night that at least cannot be done, and if you choose a small range and long distance, then with the combined firepower of the No. 3 and No. 4 lines, you can also hold on.

Most of the heavy weapons in Line 2 have been retained and successfully moved to the final line of defense, and although most of these weapons are overloaded, when the passage is dug, the heat from the overload will be removed and the weapons will be put back into service.

The addition of most other weapons will make the entire defense line more stable, and the offensive channel that the monsters can open up will not be very long, and the width will be limited, and this is their respite, they only need to hold on for a day to succeed, waiting for support.

And it is speculated that the monster that has only reached three mutations has an IQ of 10 points, and the remaining monsters in the area of the No. 2 defense line have cleared an empty area.

And those monsters did not go forward, but began to dig underground, just as they did when they first broke through the city gate and the core area, building a huge hollow passage directly underground, and directly connecting to the outside of the core area.

Through this passage, the excavation speed from the group is rapidly advanced, because most of the underground belongs to the type of Shashuo, and after being stabilized by the monster's specific liquid saliva, a temporary passage has been formed, and the pressure bearing of this passage is also guaranteed to a certain extent.

Compared to the load-bearing walls made of solid materials and the steel pressed above, the sand on the ground was obviously easier to excavate, and it turned out that it didn't take long for a huge cavity to form underneath, a large number of monsters poured in, and the area originally carried by those monsters was relatively close to Line 3.

So it only takes a large area of corrosion, and the area away from the No. 3 defense line is enough, and when the smell of corrosion reaches everyone's nostrils, the soldiers who originally wanted to lie down and rest for a while have disbelief in everyone's eyes when they smell this corrosive smell.

Because they couldn't believe that the walls that had collapsed from the external defenses, the stones were so thick, why they were corroded in such a short period of time.

Even the most powerful corrosive monsters can't do that, because once they can smell the corrosive scent, it means that the corroded walls of that monster are less than a meter away from being completely transparent.

And this meter is only a short time compared to the corrosion speed of the monster, so this smell is already predicting the location that the monster is about to arrive at and the timing of the appearance when it is defending the position and even defending the building.

At the same time, it is also a reminder to prepare for the battle and prepare for the upcoming monster attack.

Although they couldn't figure out why these monsters had dug up here so quickly, they didn't have much time to think about it, after all, everything had already happened, and it was too late to think about the reason now.

The dense network of fire was intertwined, and on the dilapidated stone wall, a deep tunnel finally appeared, and the moment the rice appeared, the monster I spoke of poured out of the tunnel and pounced directly into their position.

It was the flat plate that clenched the weapon in his hand, even if there was sweat on his forehead, even if they were tired from the constant running, they still held the weapon in their hands tightly, lonely and lonely.

At the moment when the monster appeared, they all pulled the trigger in their hands, and the crazy tongue of fire, continuous spraying, and dense fire nets killed all the monsters that rushed out in an instant.

The firepower network that gathers three lines of defense is not at all what these monsters can break through at this stage, because even the first monster that can barely reach the exit is mostly acid type, and this type of monster, their own defense is not very high.

Because they mainly relied on corrosion and acid to attack, in the face of a rain of bullets, these are no longer ordinary attacks of the blood energy weapon firepower network, and a large number of them were killed in an instant.

But with the death of the corrosive acid type of monster and the motor, the monsters behind it began to slowly rush out of that entrance.

But it often doesn't take long to fight, and it will be killed, because the ground near the exit is full of trap thorns, plus dense fire nets, even if there is an occasional fish that slips through the net, it will not cause any deflection to the entire fire net, because these monsters that deviate from the ground, the ground traps will directly solve them.

Although the defense and weapon settings have a certain energy limit, plus those concentrated heavy weapons and weapons to kill secondary mutant monsters, all kinds of weapons are in unison, and there are all kinds of weapons, even range weapons such as slowdown and burn.

So in the face of these monsters, it is impossible to break out of the line of fire, although some extremely fast monsters have launched an impact on the outside at a very fast speed, but it is still difficult to escape the fire net, and when the heavy units appear, the weapons of those heavy weapons specifically for the secondary mutant monsters will be activated.

Because generally speaking, the attack of these heavy weapons requires a certain amount of time to charge, because after the charge, this weapon will be more powerful, although it is not able to kill these monsters.

But the strengthened secondary mutant monsters are not like the previous ordinary secondary mutated heavy armor monsters, which can be easily penetrated, so for this kind of monster, it is necessary to carry out a charging design, although the interval between each attack is relatively long, but because the number is sufficient.

So the frequency of those monsters rushing out, the heavy weapon attacks can still keep up, and there is another reason because the entrance is only that big, and when the rest of the outside starts to remember the sound of corrosive acid.

The inside is actually inaudible, the monster of the three mutations has long been discovered, and it is difficult to break through by this passage at all, because the monster of the three mutations can feel that this firepower network is many times stronger than the last firepower network of the base it attacked before, plus the monsters around him now are not as many and powerful as the previous one.

Maybe if it goes on like this, it will be impossible to break through even if it takes a few more days.

casually ordered other corrosive monsters to start spitting corrosive acid on the periphery of the core, and the core was corroded from the outside in, but it didn't take long for the three mutated monsters to give up directly, because these three mutated monsters found that the entire core was extremely resistant to corrosion outside and even inside.

It is simply not realistic to want to corrode from the outside. Take a hundred plating to read the latest chapter of "The Road to Survival in the Spirit Cage", the first time to read it for free.