None of our dungeons are meant to be soloed. We have always stated that you solo at your own risk.
sense and nonsense of soloing is nothing i will discuss here.
Though, since you mention it:
One of the main reasons for partying is to have someone around who can escape in the direst of situation and return with help.
In this dungeon, it is different. Once you are in, you can't escape or call for help.
I can't stress it enough - the dungeon does what it is intended for. BUT: it is the only one with that special aspect. It is a high-level dungeon with no way to get out for a mid- and low level character/party. If you don't know what to expect, it is the worst and most deadly place i can think of. In any other dungeon you at least get a warning (you see what is there and can turn tail and run). Disclaimer: There are some monsters who nearly automatically instantly slay a mid/low level character without a real chance to escape (bodak, needle men...) - but the dungeon is even more deadly there.
EDIT: The important part here is that no one has reason to expect such a thing, since there is no comparable situation anywhere else on the server (that i know of)