"Do you know what a sine wave is?"

"Yeah. And I know that sounds are vibrations. I can maybe guess what you would mean in theory but I don't have any idea what it'd sound like in terms of any qualities that'd determine people's responses."

"Oh. It's safe for me and for the humans I've met. I'm going to go to Bar to ask to borrow a device, do you want to come with me? She's about 10 feet away."

"No, I'm irrevocably attached to this exact spot, can't you see my roots already starting to wreck the floor? Ten entire feet? No, that is far, far harder than merely traveling to other universes."

Griffie walks to Bar, holding onto Val's hand in a way that he could trivially resist if he tried. If he cooperates, ey puts his hand on a cushion at around chair height and a flat wooden surface at a highish table height, then lets go, causes the floor to move a potentially-noticeable bit, then reaches for his hand from a different angle that suggests ey's sitting on a cushion like the one ey showed Val.

"Hello, Bar," he says, then runs his hands over her.

(In Sathend it's expected and normal to touch everything and everyone. He's being gentler than he would with most furniture, but firm enough that humans mostly wouldn't get ticklish and uncomfortable. He uses his hand rather than his foot to check for supports under the countertop and doesn't try to feel the far side. This is not the level of respect he would normally show a strange table.)

The countertop has solid supports. The wood grain on the countertop and supports can somewhat be felt, though it's beneath a well-maintained finish. The supports have some decorative carvings which are plausibly some stylized renderings of flowering plants. Also, on his second pass over a countertop area he already touched, there's a thin delicate-feeling paper tube with some ridges at the ends, with small knots that would be a pain for a human to tie without tearing it, reading "Hi Val".

Aw. He pats Bar and waits for the other entity to finish up.

There is now another piece of writing (this one on food-grade twine), reading "In addition to selling products, I also offer each visitor one free beverage, and as much free water as they'd like to drink. This offer does not expire if unused."

And after a short pause, Griffie hands Val a boxy metallic and plasticky device with a handle and a button.

"What exactly do I do with this?"

"You tell me you're ready. I go to the bathroom. You carry the device on your person, open the door without leaving Bar, hold the device through the door, press the button, and wait. If there's a problem related to the device, you press the button again to turn the device off. Then once people show up, or it's been implausibly long for people to not show up and you think there's a problem, you set the device on Bar and find me in the bathroom."

He does that! Some time later he fetches em back to introduce em to an elected representative, someone taking notes for said representative, and Val's wife who did most of the actual fetching because the Milliways door is in her house.

Griffie will visibly sign on Val to greet everyone else (assuming the rest of them can see?) while keeping Val in the loop, and assume that this is at least plausibly a way for things to work as long as nobody corrects em on it. Ey introduces emself as 'the Suaal-ite' and fingerspells eir personal name, saying that the demonym should in this context be uniquely identifying.

That works and the representative does likewise.

"I'm Carey, part of Sathend's elected government, and I'm delighted to meet you. Are your people also refugees from the lost world?"

Well, if Val is okay with being a communication surface then Val can be a communication surface.

"To the best of my understanding, we are not. My world contains a planet with a population on the order of hundreds of millions, and even going back to mostly-lost prehistory, lifeforms in my world are fundamentally different from beings like yourself. Also, for clarity, while I am happy to interact with you, I do not represent anyone in Milliways besides myself."

"We'd be delighted to trade knowledge with you and maybe invite you for a visit if that's logistically feasible, regardless! But it does seem like I should also speak to Bar - is that her over there?"

"A visit may be feasible, but it's likely to be costly, as when I'm not here or in Suaal I need to work to avoid rapid disintegration. And yes, that's her. As Val has noticed, she can understand sign but prefers to communicate in writing."

"If it will make her feel more comfortable if we write her letters, we can do that. We have lots of string. Do we just place them on her when we're done?"

"Oh. No, she's fine with being signed to, she just prefers to answer in writing. And apparently knot-based language gets expressed via spontaneously appearing twine, usually she does spontaneously appearing napkins with ink on them."

"Interesting! Thank you."

"You're welcome. Feel free to ask me questions as needed, and while my capacity to assist any individual is limited, I may be able to spare time or other resources for some problems."

She thanks them again and goes off to talk to Bar, taking her notetaker with her.

"You know," Val says, "being at risk of disintegrating wouldn't necessarily be that much of an obstacle, everyone else is too. It's not our world, we don't belong there either."

"Huh, that's interesting. What's the cause of the disintegration for you?"

"I guess there's just not supposed to be anything there. There are universes that are stable in the sense that they don't spontaneously disappear and we don't live in one. - There might be more known about it but not to me."