Two weeks had passed since the zombie outbreak.
Aiden was taking deep breaths to calm himself in front of the door leading outside.
The purpose was to procure food and secure samples.
It wasn't that they were out of food right away, but because their reserves were clearly diminishing, and to assess the food situation in the surrounding area in advance, and because vaccine research had hit a wall.
Research conducted without samples had clear limitations.
Thanks to analyzing zombie behavior patterns and physical and intellectual abilities over the past month, Aiden and Jane had enough theory to deal with zombies.
However, it was still just theory, and when it came to actually putting it into practice, it was inevitable to feel fear.
But Aiden had a reason why he absolutely couldn't back down.
"Should I go after all?"
"No, it's okay."
Jane seemed to want to go herself, as if she had no fear.
But that was something Aiden could never allow.
"Jane, we've been lucky so far, but that luck will eventually come to an end. That's why I have to go. Eventually, a situation will come where one of us has to open this door and go outside. If so, it's right that I go."
Aiden couldn't send Jane outside.
Just as it would be for Jane, Aiden also had no confidence in surviving this zombie world without Jane.
He checked his equipment one last time.
In one hand he had a submachine gun, on his thigh a pistol, and tucked into his waist was a police baton that the security guards had used.
His body felt so heavy it was as if he was carrying sandbags all over.
However, this level of armament was, if anything, somewhat insufficient for going outside now.
He wanted to take more emergency submachine guns and pistols, but this weight was just the right compromise.
Any more would hinder movement, and if Aiden took the emergency weapons too, there wouldn't be any weapons left for Jane to protect herself.
"You have to be careful. If it's dangerous, run back without looking back. Did you pack everything? You know zombies are sensitive to sight like humans, so stay out of sight first, right?"
"I know, Jane."
"And when you get here, knock on the door as promised? Three knocks in a row, then two."
"O-of course I know that."
Aiden seemed to have forgotten that part due to nervousness.
The research facility's door is a thick iron door, so you can't see outside. But there's no separate doorbell either.
There are only two ways: either you have an employee keycard or someone inside opens it for you.
Aiden couldn't take the keycard with him.
Because there might be unforeseen circumstances.
Aiden glossed over the fact that he had forgotten and took a deep breath.
"Don't worry too much, Jane. I'll be back quickly."
"What are you saying! How can you not worry if you were in my position?"
With those words, Jane hugged Aiden.
"If you die, I'll be left alone. So, you absolutely can't die. Absolutely not. I don't care about food or samples..."
"Yes, I feel the same way, Jane..."
Aiden, breaking away from Jane's embrace, opened the iron door slightly.
Creak
Aiden opened the iron door slowly bit by bit to make as little noise as possible, and looked at Jane one last time.
"I'll be back."
"Be careful."
"Yeah..."
Thud
The iron door closed.
Although they chose this spot because there were the fewest zombies right in front of this iron door, Aiden tightly gripped the submachine gun and moved along the planned route as he once again faced the sight of ruins, corpses, and zombies scattered everywhere.
There's a large 8-lane road like a plaza in front of the research facility, but going that way would be the same as going to die.
So, he moved towards the side of the research facility where there were low commercial buildings.
This area had many abandoned cars and was easy to move while hiding.
Additionally, from what they had confirmed from the rooftop, this direction had the fewest zombies.
Aiden's first destination was a convenience store about 2 blocks away.
First, to see if there was anything that could be used as food there.
The second goal was to bring back parts of zombies in the vicinity that were severely damaged or unable to move as samples.
Aiden maintained a very low posture and moved about 1 meter using damaged cars as barricades.
Then, he looked at the rooftop of the research facility.
Jane's figure could be seen there. It was a kind of observation post to monitor the outside situation.
Soon her OK signal came down, and Aiden quickly moved to the next cover spot.
Pitter-patter
"Huff... huff..."
Although Aiden had been doing exercises he usually didn't do in preparation for this day, perhaps because he was too nervous, those efforts seemed meaningless as he was already out of breath.
Aiden caught his breath for a moment and slightly raised his head to look across.
There didn't seem to be any zombies visible in the situation he could see.
-Grrk uhhh
Aiden quickly lowered his head.
A voice that sounded like human vocal cords mangled beyond recognition.
Without even looking, it was a zombie's cry. The fact that it was audible to him meant it was quite close.
He looked at the research facility rooftop again, but there was no particular gesture from Jane.
That means zombies aren't visible in Jane's view either.
"Phew... This is why practice is difficult."
Aiden shouldered the submachine gun and slowly raised his head again to look across.
As expected, no zombies were visible.
Inside a building? Or is there another blind spot?
In any case, the location where the sound was coming from now was right in front of the commercial building, which meant that if he went beyond this car and turned the corner right ahead, there might be a zombie.
Aiden's hands holding the submachine gun were full of sweat from the intense tension.
They had composed countless simulations based on their observations of zombies so far to prepare for when they would face them.
However, Aiden's mind went blank now. He just moved forward.
Aiden, who had been breathing heavily until just a moment ago, forgot even to breathe as he shouldered the submachine gun more tightly and walked towards the corner.
Clang!
Was it a problem that Aiden had walked looking only ahead without thinking? He kicked a can that had been abandoned nearby.
-Grr?
Aiden was terrified.
'You damn stupid idiot!'
He berated himself.
Scared of zombies that hadn't even appeared before his eyes, he had forgotten the basics of observing his surroundings carefully and advancing cautiously.
Thinking about how Jane would look at him from the rooftop, whether she would find him pathetic, Aiden felt anger rising.
And immediately, there was a sound of something moving.
Aiden quickly turned the corner.
"Hup!"
As soon as he turned, a zombie appeared right in front of him.
The zombie's reaction was unimaginably fast.
-Graaah!
The zombie immediately grabbed Aiden's shoulders with both hands and thrust its face forward to bite his neck.
"Ahhh!!"
Aiden struggled.
In this state, he couldn't use the gun.
But when life is in danger, do people exert superhuman strength?
He kicked the zombie away with all his might.
Crash
-Grah!!
The zombie was pushed back and fell.
In that brief moment, Aiden instinctively raised the gun muzzle towards the zombie's head.
The zombie's weakness is the head, precisely its brain. Zombies can move without a heart or internal organs, but they can't move or live without a brain.
Bang!
Splat!
The bullet from the submachine gun he fired in single shot mode hit the zombie's head directly.
With a brief twitch, the zombie's movement stopped.
A headshot with just one shot, Aiden couldn't hide his surprise.
But he couldn't be happy about the situation.
Aiden drew the dagger from his waist, immediately cut off fragments of the shattered head and put them in an experimental bag, then put it in his backpack and got up to look around.
Other zombies might have been stimulated by the sound of his gunshot.
He had to quickly get away from this position.
Aiden quickly turned the corner and waved his hand towards the rooftop where Jane was.
To signal that he was safe, that there was no problem yet.
After signaling like that, Aiden started running.
Aiden wanted to calm down the emotions full of excitement. In this state, he could easily lose his life.
Calmly, more calmly, Aiden tried to calm down by breathing deeply.
He couldn't die here leaving Jane behind.
Aiden steeled himself, thinking that he must return alive no matter what.
* * *
It was fortunate that he had moved quickly away from where he killed the zombie, as Aiden arrived at the convenience store without any particular problems.
He was more worried about the way back, but he thought it was fortunate that he had secured a sample and arrived safely.
What was even more fortunate was that there were no zombies inside the convenience store.
"This is unusable... and this is inedible."
Aiden thoroughly searched the inside of the convenience store.
Fortunately, he was able to find some canned goods, and he found some items needed for daily life and swept them into his bag.
And he was able to find the most important item, which was a portable map.
Having a map that can be used portably will be a great help for future survival.
While doing so, he looked for traces of any survivors, but no such traces were visible.
There were just dried-up corpses, and corpses that had been zombies with traces of being eaten strewn about.
The interior of the convenience store was a mess, but more than that, the blood splattered on the walls or drying on the floor made Aiden's skin crawl.
"First goal, second goal, both well accomplished. Well done, Aiden."
Aiden praised himself.
He even smiled for a moment, thinking that he could show Jane the image of a dignified man.
But he couldn't waste any more time.
"I need to go back before it gets later... I wonder if I can return by the same route..."
The gunshot from the first zombie fight would have rung out loudly.
The zombies sensitive to sound would surely have gathered there.
Aiden took out and unfolded the portable map he had picked up earlier.
"If I detour around here... this way might be dangerous because it's a big road, so then..."
Aiden looked at the map and quickly drew routes here and there with his hand.
"Okay, let's get going slowly."
It hadn't even been an hour or two, but his whole body felt as heavy as a wet cotton ball.
Considering the significant physical exertion, from now on he had to move quickly unless it was a really dangerous moment.
So Aiden left the convenience store and moved in a different direction from the planned route.
He moved using wrecked cars as cover, but this time he ran, quickly passing between the cars.
And fortunately, without encountering any zombies, he arrived one block in front of the research facility.
If he just passes the corner ahead, the research facility will be visible, and when he shows Jane on the rooftop that he's arrived right in front, she will prepare to open the door on the first floor.
"Huff huff... huff huff!"
He took a deep breath before turning the corner.
And he poked his head out to check the research facility.
"Damn it..."
In front of the iron door he needed to enter, four zombies were standing guard.