Nah dude, you’re not a bother! I love getting questions, and thanks for the praise!
Here’s a quote from the author’s note (I know you just read it, but it’s been awhile for me so this is helping me get my thoughts together): “Also, keep in mind that Eridan is an unreliable narrator. What was going on in his head wasn’t actually what was happening 100% of the time; it was just how he was comprehending it.”
Here’s something that will always be true in my writing: Eridan is an unreliable narrator. He makes everything about himself, always tries to make himself the hero so he can live with himself, and he must believe that he’s constantly doing the right thing, or else Bad Things will happen. He exaggerates a lot, so sometimes things seem a lot more hopeless than they actually are.
Now to the actual writing. It’s probably my fault that you can’t understand, because most of it is pretty subtle and honestly, I doubt I would’ve figured it out if I was reading it and not writing it. About 99% of my allusions to the truth of the matter happened once Eridan and Feferi entered the building, but the first one is right before: “and that might be a good thing because you hear the fire escape starting to rattle even though no one else has arrived in hours.”
The way I see it, that phrase could be taken in two ways--one, there are zombies heading up the fire escape; two, someone else (someone alive) is coming up. A messenger? Reinforcements?
…A delivery, perhaps?
Here are some other little snippets that allude to something (what’s in bold are important words):
"…the room quivers. You feel it vibrate to your very core…”
"The room shakes again, as if the mob is moving as one and is stomping hard enough to emanate an atom bomb.”
"…people on the roof two floors above shouting…”
"…the building’s periodic shaking…”
"People call out…”
Okay, so the building is shaking. There are a lot of zombies in the building, but is that really enough to shake it to the extent that Eridan is describing? Sure, he could be overreacting for dramatic effect (as per usual) but maybe he’s onto something.
Now, onto the bold parts. First of all, a horde doesn’t “move as one”, per se. The majority of them stay in the same place because usually there’s prey, but they’re not a marching band or a flash mob-- they don’t have coordinated movements. They move erratically, dissonantly, and they certainly don’t make sure they all stomp their feet at the same time, even if that’s a good way to startle their prey (or make them think they’re in the music video for “Thriller”).
Also in the same ballpark is the word “periodic”. That word means that there’s some sort of timing and order to the building’s shaking, and zombies don’t have the ability to pull that sort of thing off. If Eridan wasn’t fucking nuts at this point, maybe he would’ve noticed that.
Then there’s the word choice used for the people still on the roof. “Shouting” and “calling” don’t quite incite fear the same way “screaming” and “wailing” do, and I picked those words for a reason: even though in Eridan’s world they are being overwhelmed, that’s not necessarily the case. Sure, “shouting” can be associated with fear (and more often, anger) but you know what it also can allude to? Victory. Relief. Jubilance.
Lastly, there’s the word “bomb”. The shitty analogy that word wasn’t included just for shits and giggles; it was a hint, perhaps pertaining to the rattle of the fire escape on the roof earlier when someone was coming up.
So something was definitely going on that Eridan wasn’t aware of. I think I’ve pretty much cleared up any confusion stemming from the “but wait, there’s more!" author’s note, but if not, feel free to enquire further!