She follows any directions exactly, and pays attention to what she can perceive of her part in this. 

How well does the first test work?

On the first try, the flame gutters out before she makes it more than a couple steps. On the second, Ellyn has to hurriedly douse it when it starts threatening burn up Gideon's whole arm. The third, it refuses to take at all.

"...I think there's a time variable component we're missing."

She has thalergy to spare, but... Maybe it needs to be looped back in? For some reason? 

Mrr. Problem is that Gideon's the one holding it, not Ellyn. And Ellyn is not pain-resistant enough to hold the fire herself.

They could try it with Ellyn's hands right under Gideon's? 

A closer look at what it's doing moment-by-moment would be helpful, if nothing else. And if she's right there Ellyn... might... be able regulate Gideon's thanergy transmission.

Worth a try. 

...Wait, would using the Transference theorem help? With the regulating. 

That- is a good idea. Yes, as long as maintaining it isn't more attention-expensive than the benefit she gets from the inside view.

Worth a try! 

Then into position, and Ellyn will crawl inside Gideon's brain before she picks up some more fire.

She's very good and doesn't get distracted by any of this. (She also pays fascinated attention to the new play of light over her hands and around the flame.)

Ellyn takes a moment to get used to the connection and stabilizing the fire.

"I can walk, I think. But you'll have to steer us."

She nods and turns all her attention to that task. "As you wish, my penumbral queen."

Then slowly, carefully, Ellyn cupping Gideon's hands cupping an imperishable flame, feeding out her death slowly, carefully.

It's beautiful. (This is beautiful.)

It is.

And slowly, carefully - she guides their bodies and their cupped hands and their shared flame towards the other chalice.

When she dips in, the fluid lights with a soft whoosh, and she can see the shifting interplay of light as a dormant theorem takes over powering the flame.

And then there's a bang and a plasticky trumpet cheer and a spray of colorful paper strips burst out from the ceiling in the middle of the room along with a key dangling on a silken rope.

She startles, then bursts out laughing. "I like whoever designed this one!"

"If you say so." Ellyn drops the theorems she was maintaining, forehead tinged with blood sweat. "They've got some kind of sense of humor."

"I like their theorem work, too, even if it is flesh magic." Working together like that had felt right. 

"Surprisingly elegant, for something so squishy."

"It builds well on Lab Two's theorems, also."

"So maybe they are supposed to be done in order."