Just got a chance to review my old saved games and try different scenarios...
Arrrgh! My apologies, guys -- I had forgotten the secret aqueduct entrance/exit. BT and Kaldire are correct; BT & Klytos _did_ think of everything!
I knew the Rogue and Sorcerer could unlock the doors at the top of the aqueduct, but not the Brigand. However, regardless of class choice, if you wait long enough, Voleris will open the door and makes her rounds up there. This allows for entry INTO Tyr... so long as you hide from her!
Of course, getting OUT of Tyr was the trick. Again, I knew the Rogue and Sorcerer could unlock the maintenance door next to the library, but not the Brigand. After playing again, this remains true for the Brigand... but ONLY for the DAY & DUSK periods!
I had never tried it at Night. During Day and Dusk, the message says it's locked. However, at Night, you can force the door open and make your way to the top of the aqueduct!
That was my fault for not exploring more and trying more things. However, after being denied twice (Day & Dusk), who would have thought it would have worked a third time at Night? Perhaps a message something along the lines of the following would have been an appropriate hint/guide here for the Brigand during Day and Dusk:
Sure, you COULD break it down here and now with your mighty strength, but someone might see you! Why don't you try again later when there are fewer people milling about?
Anyway, thanks for listening, and we can't wait for
Roehm to Ruin. I especially liked the picture you posted to Twitter last week, BT.