Going back a few moments before Saya frantically started the van and drove away in panic, terrified at the horde of undead following them behind...
After reaching the roof of the single-story house behind Imamura's house, all Nach, Imamura, and Alice's family had to do was jump down to the other side of the house into the street and run away from the slow-moving horde of undead.
Or so Nach thought.
Getting down from the roof was the easy part, since the front yard of the house wasn't swarming with undead yet.
With Nach safely landing on the ground first, he easily caught Alice and even Mrs. Maresato as they jumped from the roof, even before Imamura and Mr. Maresato could climb down, hanging on the gutter and stumbling on their fall.
Running from the supposedly slow-moving horde of undead, however, was the questionable part. After all, they weren't slow at all.
As soon as they made it past the house behind the Maresato residence, even before they could reach the corner of the street...
—ROOAAARRRR!!—
A loud, terrifying roar echoed from the undead as if they had realized their prey had escaped their trap.
The desperate undead all became aggressive and chased their prey, running like crazy and unable to make a turn as they stumbled over each other at the corner of the street, which gave Nach and everyone a bit of time to widen the gap between them and the avalanche of undead as they desperately ran for their lives.
—"Hurry up and start the van!"—
---
"What the heck was that?! Are you trying to get us all killed?!" Saya shouted, retorting at Nach as she tried to overcome her fear with anger.
Seeing Saya's terrified expression—her eyes only focusing ahead and not on her surroundings as she kept stepping on the accelerator and driving the van at full speed with her trembling hands—made Nach realize that the avalanche of undead wasn't their only concern.
"You're gonna get us all killed if you don't slow down, Saya!"
"Don't you dare raise your voice at me! If you want to die, then die alone! Don't drag us to your grave!"
"Stop the van or this will be all our grave!"
At Nach's remark, Saya hit the brakes—SCREECHHHH!!—abruptly stopping the van as its tires slid on the road before they could hit the wall at the corner of the street.
"Is everyone alright?" Nach said, looking at everyone inside the van from the passenger seat.
Beside him, Saya was still terrified, clutching the wheel with her trembling hands and still stepping on the brake even though the van had already stopped.
On the middle seat, Seko was supporting Karen, who almost slipped down her seat. Her dog, Zeke, though, totally slipped from Karen's arms but landed on his feet like a cat. Cramped in the back, Mr. Maresato held Alice while Imamura grabbed Mrs. Maresato to keep her from slamming into the back of the seat.
"They won't be able to follow us," Nach said as he looked outside and saw no undead chasing behind them, nor any around where they had stopped.
"So you don't have to be scared anymore, Saya." He added, attempting to ease her fear and calm her down—only for Saya to retort back at him.
"Don't jinx us like that, idiot!"
---
The instant Saya calmed down enough to drive without panicking, they continued heading back to Rika's apartment with the sunset behind them, trying to get there before it got completely dark.
"What's wrong with him?" Saya asked as she glanced at the rearview mirror and saw Imamura, who was now sitting at the extra seat beside the door, looking dejected and grieving.
"Aren't they his family?" she added, directing her glance at Alice's family and her question at Nach.
"They are now," Nach said, making sure Imamura heard his words.
It doesn't take someone to be a genius to understand what Nach meant, and for Saya—who is one—she could only glance at Imamura with sympathy, worried at the thought of her own family's safety as well, until she suddenly felt someone patting her head.
"Stop touching me and don't treat me like a child." she retorted once again, shoving Nach's hand away despite understanding that he was easing her worries without mentioning that her parents were most likely fine so as not to offend Imamura.
---
[Porushark Writer's Note:]
I tried to do some research about the layout of Rika's apartment and here's the closest one I found. Look at the comments.
I'm not sure if it's only one floor in the anime. But in the manga, it seems to be two floors, and that's what I'm following.
---
"Can you do it, Saya?"
"It'll be a piece of cake, for a genius like me."
At her remark, Saya stepped on the accelerator—BAMM!—ramming the van into the swarm of undead gathered on the street in front of Rika's apartment, its front window cracking even more upon impact—SCREECHHHH!—then stepped on the brake to stop the van with its side door right beside the gate of the apartment building, creating a barricade so the undead wouldn't be able to break through the gate easily.
Right then, the side door of the van and the gate opened at the same time.
"Welcome back, everyone," Shizuka said, greeting everyone as they stepped out of the van.
As soon as Nach stepped out of the van, he rushed to embrace Shizuka.
"Aren't you gonna ask me something?" Nach said, making Shizuka look up at him, tilting her head in confusion.
Not that Nach was expecting Shizuka to understand what he meant, so he leaned down and whispered it into her ear.
"It won't be dinner nor bath… but you first, Shizuka."
Seeing Shizuka completely flustered, her face and ears blushing red, Nach couldn't help but grow more aroused and excited for the night.
"Stop sexually harassing Marikawa-sensei, pervert," Saya grumbled as soon as she stepped out of the van.
"Aren't you Hayashi-sensei's lover?" she added, voicing everyone's concern—except for Alice's family, who were unaware of the situation, but including Karen, who shared a slightly different but still similar concern.
"Is that a problem, Shizuka?"
With everyone's attention on her, waiting for her answer, even Shizuka couldn't help but feel embarrassed. Still, she didn't push Nach away and indulged herself in his embrace as she gave her response.
"No…"
"You perverted adults!"