"Oh, I apologize. I underestimated your ability to grasp basic conversation and interpreted your humorous response as social awkwardness."

Snort.

"Please proceed to the next chamber."

Yes, that is the thing that she's doing.

Down to the elevator!

"Did you know that people with guilty consciences are more easily started by loud nois—" And there's a sudden, loud train horn noise coming from everywhere.

She snickers, mostly inaudible under the noise.

It stops. "I'm sorry, I don't know why that went off. Anyway, just an interesting science fact."

"I think you are making that up."

"Oh, most certainly not. Aperture Science regulations requiring me to stop enhancing the truth have been active for the past... several hundred years."

"But if they weren't, how would I tell?"

"I suppose you wouldn't. You only have my word for it."

"And you've certainly never given me any reason to doubt that," she says, dryly.

"And you can argue with me until one of us drops dead or you can do something useful. Like test."

And the elevator arrives.

She steps out and proceeds to the next testing chamber.

She finds herself at the bottom of a pit. The floor and lower part of the walls are portalable but everything above that is not. There is a laser generator pointed directly at a laser catcher, and as soon as Sable walks into the chamber the generator is turned on, which causes a moving track platform attached to a wall to move up to the top of the pit. A cube with a pink circle and a heart in the middle of each face is dropped there.

"That is a Weighted Companion Cube. It will accompany you through the test chamber. Please do not let your habit of destroying things after they bore you get in the way of solving this test chamber."

"Aww, it's adorable!"

Hmm, blocking that laser with her new companion seems like an obvious first step...

Down goes the platform to where she can reach it.

And can the application of some cleverness get her onto the platform when it goes up?

Well, the walls and the floor below the cube are portalable and visible from the lowered platform...

It's boopin' time!

As soon as the cube is no longer blocking the laser the platform starts going up. Success!

The higher level has no portalable surfaces except for two angled panels. One of them points at where the exit door is, and another at where a large button can be found. The button is on a lower part of the chamber than the exit.

"Please note that the Companion Cube cannot threaten to stab you. In fact, it cannot speak at all."

Hmm, so... retrieve her new friend via portal, fling them both up to the button, deposit friend on button—?

When she places the cube on the button, a section of wall opposite one of the angled white panels is moved outwards and upwards, forming an extension of the highest platform where the exit is.

"In the event that the Companion Cube does speak, please disregard its advice. It's a cube. It does not know how to advise humans."

"I'll keep that in mind," she says dryly.

Is it time to fling herself onto the newly risen platform? She thinks it is! Let's find out!

Yup!

"The Companion Cube should not be taken out of the test chamber, no matter how much it tries to convince you otherwise."