As you see in this topic, LanDC has found an unused loading screen of Tiger Gate Bldg.
I think I've found where it was. As you may know, Thousand White Bldg is called C Bldg
and looks like this:
While all the rooms in the building are classified as "C-1," Tiger Gate Bldg is called "C-2."
That means it should be a connected building to C-1 Bldg, like other Kowloon buildings.
I've found the answer in this map of the Thousand White Qr:
You can see this map for a second when you buy it around Thousand White Qr.
Do you recognize C Bldg? The big building in the middle is the Yellow Head Bldg
and C Bldg is just its left. Do you see the difference of its shape from the one
in the map of C Bldg? There's a connected building on its left, projecting into the
green area! That should be C-2 part, namely Tiger Gate Bldg.
In fact, you can see that part of the building from Dragon Street like these:
Isn't it strange the part that is supposed to be gone now still visible like this?
This is the closer look of the Tiger Gate Bldg. I took this picture by using the glitch
LanDC found and crossed the loading point as invisible Ryo. ;)