"Thanks!" chirps Belmarniss. "Good luck duking it out with Olgin."

"If you already cut through his hordes enough to take the rod from him, I won't need luck," she says with a smile. "Good luck on your own quest, whatever it is. Lady Ilsandre, would you lead our honored guests back through the maze?"

The Marquise nods, and does so.

Follow follow follow.

When they leave the maze, the Marquise waves. "Farewell, honorable friends! Sorry for trying to kill you!"

"Sorry for swiping the air out of your lungs! Have fun making more zombies!"

And let's go see if the puzzle can be solved now?

Back to the central chamber they go! (The dragon room is, strangely, silent again when they pass by.) Soon they're standing in front of the bridge, facing north.

R G B
W B G
Y R W
G Y R

"We don't have a red one in particular. I think any other we could make a straight path without. Red one's in the mirror room."

"The ogre was right, then. Damn it."

"Okay, who can we make least dangerous. I'll do it if I'm the best choice but I'm full of spells and don't fancy using them all up on purpose mid-dungeon in case that dragon has, I don't know, shapeshifted to make it out the door and is prowling around looking for us - Jojo can't be disarmed - Deekin, do you know Silence, it's dismissable but if you cast it on yourself in advance maybe your duplicate wouldn't be able to dismiss it?"

Deekin shakes his head. "Deekin meaning to learn it next time Deekin get new second-level spell. Deekin not want to suggest, but maybe tie Belmarniss or Deekin hands so no spells? Belmarniss have Still Spell?"

"I don't, and everything I've prepped does want a gesture. Also I'm good at counterspells and will have the same things. But if I can talk her around she'll want to write some things down, probably."

"I think it still makes sense to have her hands tied at the start, if reflections universally attack their originals; you can then have a conversation, and if she wants to write something down she can be untied."

"Yeah, just giving you advance warning that asking to be untied isn't necessarily a ruse."

"Noted and appreciated."

"I doubt it's worth the risk, but I do wonder what would happen if I were on your belt when you looked in the mirror," Enserric says contemplatively from his place at Deekin's side. "Am I equipment or a separate subject? Would I be exempt as a technical undead? Wheels within wheels."

"Let's skip that but I note its theoretical interest."

"Yes, let's."

They trek back to the Hall of Mirrors. (They're getting to know this first floor of Undermountain quite well, by now.)

Inside: a hall, containing mirrors. Two dozen of them, along both of the long walls. "We'll stay by the door," Garrus says, tying a length of silk rope around Belmarniss's wrists in a manner that suggests some amount of practice. "Try to stay a few feet away from the mirrors when you look into them, so we don't get confused about who the reflection is when she does pop out. I'll have arrows nocked, but not pulled, so I can intervene if necessary but won't be too jumpy on the trigger. And again, sorry about all this."

"Hang on, untie me, I wanna, like, pin a sign to myself."

"-oh, in case it gets mirrored? Good idea."

He unties her.

She writes herself a note; it's in her native language so none of them can read it. She pins it on.

She lets him tie her wrists again and she walks in.

The first mirror she looks in, her reflection looks just like her except that there's a pouch by her feet that isn't there in the real world, full of coins by the looks of it.

The mirror's surface ripples a little, as if she could reach right through it.

She sticks a foot in to nudge the bag out.

It works! After the bag is claimed, the mirror evaporates. 

The next one has a couple of potion bottles, one orange and one green. 

Nudge nudge.

She’s able to get one, then the mirror evaporates.

In this manner she leaves a trail of miscellaneous valuables behind her, including a rod which, while not red, is inscribed with swirling patterns and radiates a magical aura.

Then, at the sixth mirror she looks into, her reflection has nothing by her feet, but she has a strange gleam in her eye. The mirror wobbles alarmingly, and then there’s a second Belmarniss in front of the first.