Actually, they don't need to worry too much about the falling rain.
What they need to worry about would be the running water on the ground because it had already touched a lot of zombies outside.
The rain itself wasn't problematic, but the water it accumulated that had run through different places was the problematic thing.
That's also why the tap water being distributed around the water system would be problematic.
"Be sure not to let my snacks get wet," Luciel also said to Zam, who was already preparing to walk out.
"I will take them by myself so that there won't be any problems with them," Zam promised and went to call the other ability users.
Afterwards, he just sat on the sofa to wait for them to get all their things up on the second floor.
All the people staying on the first and second floors were also awakened by the rain or by the people around them, who actually didn't even sleep at all.