I don't know what to say. Just tried it and it worked. I killed the Earth Guardian in Rock Garden with my level 7 Orc Warlord, double-clicked the trophy and exited, getting the message I bravely ran and being payed 450 (x3 price for flaming), and then got the toastie that I sold it. It counted the run as a loss, because the flame is still there.
Oh yeah, Halls of Steel sometimes creates practically (or maybe literally) impossible situations. I went in with an orc monk. I started out walled in by 2 unkillablle level 2's and a level 1 illusion, which I killed. I walked down that hallway and proceded to have to fight another level 1 illusion and then had 0 damage. I got Taurog's Sword (back to 5), and proceeded down the hall. I eventaully had to fight 2 more level 4 illusions. Long story short, I lost (because my second boss was bleaty). The entire map revealed showed 4 squarish areas each connected by 2 hallways only. That is a ridiculous layout, considering the fact it forced me into a series of far too damaging kills to win. Seriously, the orb of lusory was found at level 5, so I couldn't dispell the illusions either. I'd take a look at that algorithm.
EDIT: Maybe this is google translate's fault, but "Ut sit tempura felicem terra timebat monstra" translate to "In order that there will always be a happy land that feared monsters". That makes little sense.
I speak chaos.