The structure and layout of the third floor is no different from the second floor, it is still the appearance of these hotel rooms, and the second floor is not considered to be a big gain, so the third floor is not searched carefully.

After everyone hastily killed all the zombies on the third layer, they went directly down to the fourth layer.

The structure of the fourth floor is somewhat different from that of the third and second floors, and although there are various rooms next to the corridors, these rooms are no longer resting places, but are similar to functional facilities such as conference rooms and offices. There are also some zombies wandering around these places, but they are all ordinary zombies, so they don't pose a big threat to everyone.

The imaginary mutant zombies never appeared, and the team members were both happy and disappointed. Fortunately, there were no mutant zombies, and there would be no loss of personnel, but at the same time, they also lost the opportunity to advance to level 5.

Judging from Liu Qian's previous arrangement, there should be an order in his heart, as long as he encounters enough mutated zombies, he will be promoted to level 5 sooner or later, right?

Continue down the stairs, and when you go down to the fifth floor, you can hear the oozing roar below just standing at the top of the stairs. It sounded like there were a lot of zombies underneath, at least dozens or more, and some of the timid team members looked at Liu Qian with some fear, worried that there was some danger below and suddenly rushed over, and everyone couldn't avoid it in the narrow corridor.

Liu Qian stopped Zhang Shengli and Wang Decheng, and then walked in front with Yinhe, but after going down the stairs, only two zombies pounced, they were wearing security uniforms, and it seemed that they were guarding some entrance before the catastrophe.

Since there are only two zombies. Liu Qian and Yinhe easily dealt with them. After turning on the emergency lights on this level. I finally saw what was going on with those dozens of zombies. After the stairs is an empty room, similar to a security checkpoint. Further on, there was a sturdy iron gate, and dozens of zombies in white coats or other clothes were trapped on the other side of the gate.

The iron gates are locked, so while they are terrifying in number, they pose no threat to the crowd. After seeing the team members coming down, dozens of zombies roared and tried to hit the iron gate, trying to rush through the iron gate or squeeze over and bite everyone.

But it was clear that it was all in vain, because the iron gate was very strong. They just kept shaking the iron gates and couldn't knock them down or push them open.

Killing zombies through the iron gate is the most loving, and the other team members consciously left the opportunity to Li Miao, the weakest in the team. Li Miao used a spear made for her by Zhang Shengli, with a sharp dagger tied to the front end, and desperately stabbed the zombies inside through the iron gate, and as the zombies fell one by one, a faint black mist floated out of the zombie corpses one by one and drilled into her body, increasing her strength little by little.

Liu Qian was not in a hurry, anyway, he had time, so he let the team rest in place, waiting for Li Miao to slowly stab all the dozens of zombies to death.

After killing all the zombies on the other side of the iron fence, Li Miao shook the iron fence vigorously and made a loud noise. I want to attract the zombies from the depths behind the iron gate. This tactic did have some effect, and before long some scattered zombies ran up from the depths of the ground, crawled over the previous pile of corpses and rushed to the iron gate.

But with their pitiful intelligence, they just kept pounding against the iron fence like wild beasts. Then one by one, Li Miao on the side of the iron fence was stabbed to the ground, which became her experience points to enhance her strength.

When no new zombies appeared on the iron fence, the corpses of the original zombies had almost blocked the entire passage. Zhang Shengli came over and opened the iron gate with the keys found from the two security guards.

I don't know what the process of these people's mutation was like when the catastrophe occurred, but it is possible that the two security guards outside turned into zombies first, so they didn't even have time to open the iron gate and release the inside.

If the people inside had changed first, the two security guards would probably not have stayed here anymore, and would probably have gone to the ground to report the news. Of course, it is also possible that there was a change inside the iron gate, and two security guards were sent down to guard the iron gate, and somehow they also became zombies.

Whatever the reason, the underground has become like this anyway, and there is no point in figuring this out, so there is no need to delve into anything.

"What kind of research do you think is going on underneath that would lock all these researchers in the basement?" Wang Decheng asked Zhang Shengli.

"I can't guess this, let's go down and find out." Zhang Shengli replied to Wang Decheng, and the team members dragged away the zombie corpses blocking the passage while discussing, and cleared the road inside.

After entering, looking at the layout of the laboratories on both sides of the corridor, everyone quickly confirmed that this should be a biological laboratory, and there were various animals of different sizes in various iron cages, most of which were dead, and only a small part was still moving.

But the small number of animals seemed to be very manic, their eyes were blood-red, and when they saw everyone coming in, they frantically banged the cage bars, but fortunately, the cage rods of the iron cages where they were held were very thick, so they could not rush out and attack everyone.

There are also a few autopsies in the lab, and there are even human corpses on them, except for some animal corpses, all of which are now rotting and even maggots are stinking, apparently for some time.

Seeing these things deep underground, although they knew that these dead things would not attack humans, still made the faces of the team members show horror and discomfort. The local survivors, in particular, were even more uncomfortable, and they could see that these experiments were apparently going on before the cataclysm, and perhaps the whole world was related to these experiments.

Except for disgusting animals, human corpses, and some related experimental equipment and drugs, there is still nothing to be gained from this layer, and there are no powerful bosses such as mutant zombies. At the end of the laboratory hallway, a staircase descended, and it seemed that the underground space was much deeper than everyone thought.

At this depth, I am afraid that it has already exceeded the depth of the river bottom, and the construction of this laboratory was indeed a big project.

Going down the stairs, down another floor is still the laboratory, and the laboratories on this floor look more like slaughterhouses, unlike the previous floor, which is mostly animal corpses, and the corpses on this floor that are hung up and placed on the dissecting table are mostly human corpses. (To be continued......)