Two twin Maxim machine guns have been installed, and the gate has been upgraded to look thicker and stronger.

In particular, the structure of the gate has changed from a push-pull type to a lifting type, and the entire gate has been completely embedded in the wall, and if you want to open it without lowering the gate, you have to blow up the whole wall together.

The gate, which was originally made of reinforced concrete wrapped in ordinary steel plates, has been upgraded to a solid heat-treated homogeneous nickel-chromium alloy steel plate with a thickness of 30 cm.

During World War II, the Wakoku used this material of steel as the main armor of the Yamato-class battleships, and stacked it to a thickness of 650 mm.

At that time, the armor of the main gun of the Yamato-class was 650mm thick, which no artillery could penetrate in the immune zone at that time.

In fact, the Federation found such a steel plate after the war, and in order to test the performance of this steel plate, they used the 410 main guns of the Missouri-class battleships to carry out zero-angle shelling at a distance of 300 meters to penetrate such a steel plate.

However, in the end, it is almost a century ago technology, and now nickel alloy steel has become an ordinary steel that can be bought casually in the steel market, and the price is low.

Among the materials collected by Chen Xin before, there was such a batch of nickel-complex alloy steel steel columns, which were sold as raw materials for metal processing.

In Chen's original plan, these materials would be used to reinforce the inside of the shelter in addition to the gate.

Of course, in Chen Xin's original plan, he did not plan to make the gate a 30cm thick solid metal door, and made a hollow structure with a few centimeters of steel plates, and it was enough to still have reinforced concrete inside.

But after Ding Ning gave him the note, Chen Xin's inexplicable sense of crisis made him choose to turn the gate into solid metal, even though it nearly doubled the survival points he spent on leveling up.

Although Chen Xin's gate is not as thick as the main gun armor of the Yamato-class battleship, his enemy also does not have the main gun of the battleship.

As for the use of explosives or something, it is impossible to affect such a thick armor, otherwise there would be no need to use armor-piercing shells in the war to effectively penetrate the armor of the battleship.

Looking at the gate that he could only describe as incomparably strong, Chen Xin couldn't help but scratch his head a little while feeling an incomparable sense of security, now the defense of the gate is enough, but the walls are not as strong as the gate.

However, there is no need to worry too much about this problem, after all, under his refuge location, there is a mountain more than 200 meters high above his head, and the hardness of the thick soil layer will not be much worse than that of metal after freezing.

So now as long as Chen Xin doesn't open the door, no one will want to enter his shelter.

The hydraulic lifting structure of the gate ensures the reliability of the gate, but if the power is out, it is a bit of a scratch to open the door.

Fortunately, the hydraulic mechanism of the gate lifting column has an emergency door opening device, which can directly discharge the liquid inside if necessary, so that the lifting column can fall instantly and open the door.

But this is a once-only emergency measure, and should only be used in the most critical or necessary moments, because once it does, it will be difficult to open the door and close it.

With such a solid and reliable gate, and installing Makqin as a defensive weapon on the gate, Chen Xin was completely relieved of his safety.

Back inside the shelter, leaning back on the sofa in the living room, Chen Xin had enough room to think about the ins and outs of this whole thing.

First of all, the beginning of the incident should be the attack on the No. 2 shelter in Baling County, that is, the mission where Qin Lan was injured.

Because the terrorists who attacked the shelter in this incident used a suicide attack, causing more than 20 casualties, it attracted the attention of the city government, and an investigation team was set up to investigate, and the first time Chen Xin encountered it was at that time.

Subsequently, the provincial government, which received the notification from the municipal government, was also shocked by this incident, so it sent a special investigation team from the provincial capital Xingcheng to the city, and formed a joint investigation team with the city's investigation team, and then launched a second investigation.

According to Qin Lan's words, it is very likely that the city government grasped important clues during the first survey and determined that the terrorists who caused the attack were in the area where Chen Xin's house was located, so the second survey still included Chen Xin's house.

But there is a suspicion in it, because Qin Lan was injured, Ding Ning was sent to take care of her, and the two were put on leave for a month This happened after the attack, before the city government set up an investigation team to find out.

"Did Uncle Ding and the SWAT team know in advance that this matter has something to do with me?" Chen Xinmo rubbed his chin, always feeling that something was wrong here.

It stands to reason that even if Uncle Ding wants Ding Ning and Qin Lan to protect himself, he should have made such a decision after the first time he made a decision after confirming that the terrorists were in his area.

But Uncle Ding gave Qin Lan and Ding Ning a month's vacation at the beginning, as if he knew what would happen in advance, and then deliberately found a reason for Ding Ning and Qin Lan to separate.

As for the note that Ding Ning gave him before, Chen Xin felt that this note was quite normal, after all, this was the second time that the arrangement was over, and if there was any action to arrange, there should be enough clues and information.

It's just that Uncle Ding has always loved Ding Ning, and in order to prevent Ding Ning from being in danger, he simply gave her a vacation before the disaster came and let her go to Mo Qingyan......

Chen Xin thought of the holiday, and suddenly had inspiration and connected several things.

Before the attack, Uncle Ding, as the leader of the SWAT team, probably had received information or clues from some channels, but he did not know the time and place of the attack, or did not know that the attack would cause such a large number of casualties.

So at this time, whether it was Ding Ning or Qin Lan, they were all at work as usual.

As the time of the attack happened, Qin Lan was injured, and more than 20 officers of the SWAT team and the armed police were either injured or killed, and things suddenly became worse.

Therefore, at this time, Uncle Ding sent Ding Ning to take care of her on the grounds that Qin Lan was injured, and directly gave them a month's leave, probably with the intention of letting them stay in the relatively safe place of the hospital.

This is also why Ding Ning didn't give the note to himself at the beginning, nor did he say anything about moving in with Qin Lan temporarily.

But with the development of the two investigations, it is obvious that something should have happened in the middle that Chen Xin did not know, which caused things to change.

Ding Ning's note was handed over to him at this stage, and it was obvious that Uncle Ding's original arrangement had changed.

This may be a sign that the joint investigation team is going to carry out some big operation, otherwise Uncle Ding would not have put his daughter in his own place, which is likely to be within the range of terrorist activities.

But this is not necessarily, Chen Xin's fingers tapped his knees, and after straightening things out, his thinking became much clearer, and he also had a new judgment.

What he had just analyzed was the thoughts of the police and the joint investigation team, but if he put his perspective on this group of terrorists, Chen Xin felt that they might not come to his shelter.

Because terrorists, as insane as they are, are not insane, and they must have a goal when they can attack official shelters and commit suicide attacks at the cost of a dozen lives.

Whatever the goal, suicide attacks are likely to be just the beginning, because a dozen or so highly trained and courageous suicide attacks are invaluable to a terrorist organization, and cannot be wasted without such a plan.

So the first attack they made was probably to attract the attention of the police and the city.

So assuming that their goal is achieved, and now the attention of the city government and the police has been attracted to Baling County, it means that the attention of the city government and the police has declined to the urban area.

Chen Xin felt that the answer was already obvious.

Thinking of this, he couldn't help but be a little worried about his friends in the city, especially Mo Qingyan and Mo Qingxin, the two of them lacked strong enough defenses, and the two of them had no resistance, if something really happened, the two of them really had no ability to deal with it.

Why don't you let the two of them come to you for a while?

Chen Xin considered this idea, but hesitated.

On the one hand, the Mo family sisters may not be willing to come, and on the other hand, if he has to live with five people, and if four of them are girls, it will become very embarrassing for him.

However, considering the danger that might occur, Chen Xin felt that it was better to wait for Qin Lan and Ding Ning to come and discuss with them before making a decision.

Just like that, where to live......

Chen Xin couldn't help scratching his head, he finally upgraded the bedroom, but did he still want to sleep on the sofa?

But this is all for later, now Chen Xin feels that he should still prepare for Ding Ning and Qin Lan to come and live first, after all, they are two girls, and some things still need to be prepared.

This inevitably made Chen Xin feel troubled, but the arrival of Ding Ning and Qin Lan could not be said to be without benefits, at least these were two people who could work, although they were only temporarily staying, they could help themselves share a lot of things in the shelter.

At least there are people to help with many things in the planting greenhouse, and Chen Xin doesn't have to be busy from morning to night alone.

And with other people in the shelter, it can be a lot more lively, with someone to chat with and play games together during the evening break.

To be honest, it's good to play games alone, but it's even happier when you have someone to play with.

Thinking of this, Chen Xin couldn't help but look forward to the arrival of Qin Lan and Ding Ning.