Where's the bathroom?

[Steve]

No: HPFGUIDX 45451

I'm winging it from memory here, although I am in the process of
reading CoS again. I hope I don't mess this up.

Hermione said Moaning Myrtle's bathroom is on the first floor. I
assume that's the British first floor which is the American second
floor. It's the floor above the ground floor.

Next when Harry comes up from the dungeon (CS: death day party) and
hears the Basilisk, he runs up from the dungeon then up the marble
staircase. This puts him on the British first floor/American second
floor. This should be the level that Moaning Myrtle's bathroom is on.
Then they run up another staircase following the voice and down to the
end of a hallway. Here they see the writing on the wall and the dead
cat. All this is outside of Moaning Myrtle's bathroom.

So is that bathroom on the ground floor, second floor, or third floor?

Next, I brought this up before in another thread, but no one seemed
interested. I'll bring it up again and let the chips fall where they may.

When the feast ended, why did all the students go down that particular
hall? A hallway that appears to be on the third floor. (British:second
floor; American:Third floor. Up two flights of stairs from ground level.)

The Slytherins, for example, go DOWN to the dungeons from the main
entryway. I think, Ravenclaw, and Hufflepuff also go down from the
main entryway to get to their dorms. So why did they all go up two
flights of stairs and down those hallways? They seemed to come from
two directions; coming from two directions seems to imply that
Harry/Ron/Hermione were at the end of the building or wing, and the
students came down two parallel hallways. So where were they all
going? Why would the whole student body go down a hallway that doesn't
really go anywhere?

Really, I don't have a clue.

bboy_mn