If the scenario starts to run overlong, Torvic's jumbled memories may gel enough to suggest where the Lady Morilaeth's revel is being held.
Additionally, the derro torture-sage is no great supporter of his nightmarish leader: Skilled diplomacy or roleplay may convince the vile researcher and his thralls to stand aside while the party heads upstairs to the Masque of the Pallid Measure. Of course, the party needs to get Torvic off of him to pull this off.
A group with additional time for play might choose to add a horrific "dream sequence", taking advantage of Morilaeth's deadly power over night terrors. Once Lady Morilaeth knows of the party (probably from a fleeing mite), she can try to stalk them in their dreams. If the party chooses to rest, one of the party members could be targeted by night terrors, while the rest of the party is only present in the victim's dream. I wouldn't reveal who the real victim was until the scene ends (and he begins rolling saving throws) and I wouldn't tell them it was a dream: They'll figure it out soon enough.
Foreshadowing the Masque of the Pallid Measure... "Orchestral music awakens you, and you find yourself in an opulently-decorated ballroom. You're all seated at a feast table piled high with delicious dishes. Each of you wears a brightly-colored costume and ornate masks cover your faces.
Festive figures wheel and twirl across the dance floor as dwarfish servants pour wine and deliver trenchers filled with desserts. Beyond the revelers, an elegantly-clad woman urges her guests to enjoy themselves."
The revel continues until one of the PCs decides to take off their mask (or it becomes tiresome, in which case the revelers begin shouting "unmask!" The unmasking reveals each of the revelers (and the PCs) to be a ghoulish figure, which immediately begins attacking and devouring those around him. The "delicious food" on the table is revealed to be maggot-filled carrion. Blood flows copiously from the wounds the revelers (and PCs) inflict on each other, covering the floor. Shapes seem to rise from the spilled blood, arms pulling struggling victims into the floor beneath them.