Right away, there are no SCPs in the three thousands, yet.
externally appearing to be an office building
This is worded a little awkwardly. Maybe something like "disguised as an office building"?
three (3)
The "(3)" is unneeded.
from level 3 or higher
I don't know if this would be the proper way to word this, in context. Clearance is usually described as being leveled. Maybe "level 3 clearance" or "from personnel with level 3 clearance or higher"?
permitting testing
Like, permission for them to supervise tests or be tested? I don't think any rando with the wrong paperwork would be very happy to sacrifice themselves to science.
five (5)
Again, unnecessary, but not necessarily a bad thing as long as you are consistent.
SCP-3333 is an underground chamber in ██████, Egypt, found approximately 23 meters below an urban district, with construction dating to approximately 2700 BCE.
This sentence is a little long. I would make it into two.
12x8x15
Like the numerical characters in parenthesis, the lack of spacing isn't really an issue as long as you are consistent with it.
two curved spines
Like the bones or like spikes?
from the sides
A little vague.
which remains untranslated
You accidentally crossed-out the space in front.
16 raised
Be consistent, remember.
human bone
… how
and [DATA EXPUNGED]
and potato salad?!
similar to a young human woman
exactly one person is set between the spines of SCP-3333-1, and exactly one person is seated on SCP-3333-2
That must have been quite a coincidence the first time this was discovered.
becomes flush with the floor
Maayybbe tone error. Idk, I feel like there is a better way to say this.
33 seconds
I'm sensing a pattern, here.
Kasto Ghannam and Hussein Hakimi mistakenly activated the anomalous properties of SCP-3333 by standing and sitting on SCP-3333-1 and SCP-3333-2, respectively.
What a remarkable coincidence.
later able to report to Foundation agents
I hope he didn't know who they were.
hieroglyphic script in use during Egypt's second dynasty
Who was Pharaoh, though?
believed at the time of SCP-3333's construction to be the receptacle of the human identity and soul
It is a little more abstract than this, but not entirely wrong.
during their research
While not wrong grammar-wise, you already stated that Dr. Blackbox is a woman. Why make it gender-neutral all of a sudden?
1903 by Calvin █████████, a British explorer and anthropologist. Calvin █████████ had not discovered the entrance to SCP-3333, but he described the temple above the chamber, which later collapsed in 1912.
So he just dicked around doing anthropologist things for nine years?
Indicated by surrounding symbols to be the goddess Isis.
Why? I mean, there's clearly some mystical shit going on, so is she there because of the magical aspects? Is it a temple to her? What symbols/words gave someone the impression that this is Isis? I'm also not entirely sure that Isis was a major deity during the second dynasty. I know worship of her grew as she became the wife of Osiris over the years and that some cults still followed her during Roman occupation, but I have no clue about this time period.
In each version, a powerful member of the community offers a human sacrifice to an undescribed being in the temple in order to gain insight to their future.
Google Chrome is telling me that "undescribed" isn't a word. Also, this was going on when there were foreign rulers in Egypt and nobody knew about it? Even if it was in the middle of nowhere, someone would have heard of mysterious disappearances.
Turkey
How'd he get to Turkey in a small motorboat?
the reckless expenditure of D-Class subjects proposed in Kalter's research proposals
This seems a little cliche what with the sadistic doctor and all.
