A short while after Baern leaves, a Kenku serving girl brings in a tray with the drinks and closes the door behind her.
After placing down the drinks, she heads back to the door and grabs the doorknob:
"You shouldn't have come here. They'll spot you sooner or later, and they don't care who gets killed in the process. If you want more answers, you'll need to head downstairs through the kitchen. Go to the room with the old vat in it."
Before anyone can stop her, she quickly opens the door to head back out.