There was connection path from ONC 2F to OC 3F bottom left door.
The OC 3F bottom right door went to Bichon Dead Mines (in the back there is this square like map that is the end of this path at the Dead mines end).
SV mines 2F at the bottom right was exit into connection path that led to BC 1F, halfway along this path was a secret turn off to Magic Cave.
ST 3F stairs went to connection path leading to Sabuk secret three exits, one behind the shop building, second behind the little junk shed in upper left corner of Sabuk enclosure and third was outside Sabuk walls enclosure (@ upper left corner near where the junk shed entrance inside was).
I believe this setup at Sabuk end meant you could infiltrate Sabuk during a war from outside its walls and come out inside either at the junk shed or the shop location. Alternatively you could start at ST end but that wasn't easy to get through. Don't know if that was ever utilized as I didn't take part in these wars.
I recall Porcelain (I believe war char) boasting he was the first to get through from ST to Sabuk. He might have been lev30+ Problem was that you ran out of pots somewhere along the way.
At ST end as you stepped in, it was tough fight right away since it was chock full of ST mobs, deeper in they mixed with zombies until at Sabuk end was just zombies.
I wonder if Jev's database has all these connection paths reconstructed.