That doesn't seem to make it be happening any less.

If it suddenly disappeared that would arguably be even weirder. She takes a step into the bar, notes that according to her ring she isn't stopping anything bad from happening, and walks farther in and looks around. The view of exploding stars out the window is extremely cool.

It really is!

When she lets go of the door it swings shut and then pushes open again.

"Hello. Do you know what this place is?"

"No, and it should've been impossible to do this in the Dome -" She reaches for the door handle, which has ceased to exist behind her.

"What's the Dome--?" Oh no, the door is trapping them in here. She tries wanting it to stop doing that for a moment, then worries that she might stop the entire bar with them in it to who knows what effect and tries to not want anything.

"Dome's a big, uh, dome, covers the palace in Sothis, blocks teleportation and suchlike, shouldn't have been a way to - why me I'm not even pregnant - who are you -"

"I'm Margaret, I've never been to any palaces or anywhere called Sothis and I'm as confused as you are."

"Sothis is the capital of Osirion. Uh, on the Inner Sea, do they know about the Inner Sea in - Tian Xia?"

"I'm from the United States and I thought I had a decent geography education but I've never heard of any of those places. Are you from an Avalon?" Presumably this woman is a critter since she thinks teleportation is normal.

"No, I'm from Sothis. Big city." She's feeling around the edge of the door. "And I have been impossibly kidnapped out of my family's palace and I don't care for it at all."

"Yeah, this is pretty creepy." Margaret is debating whether to offer to try to teleport them out, but this bar wouldn't fit in her parents' kitchen and she's still never teleported into or out of an expanded space and she really doesn't want the first time to be with a passenger and a lot of other weird stuff going on. "Hello? Is anyone else here?"

No voices call back.

She walks up to the counter and examines it. There's nothing behind the bar where you would normally expect shelves full of alcohol, and nothing on the bar where you would expect a cash register or something, and overall this whole place gives off an air of "faked up to mess with people without a ton of attention to detail".

When she gets close enough to touch the bar a napkin appears on its surface, suddenly and silently as though added between frames in a movie.

Okay, so someone is watching and capable of teleporting things in here. And the thing they chose to teleport was a napkin. For some reason. She picks up the napkin and examines it.

It says Welcome to Milliways! Can I get you anything? The first drink is free.

"Hey, uh, I never got your name, also there's a magically appearing napkin offering us free drinks and not explaining why we got kidnapped." 

"Ismat. Uh, I don't have anything on me for detecting poison."

I'm sorry, I don't control the behavior of the door, says a new napkin. It seldom declines to open for a given patron for more than a subjective day. I don't dispense poison, though I have nothing but my word to offer on that.

"Yeah, me neither." Margaret hands Ismat both napkins and checks if her phone has signal.

It does not.

"- well, who does control the behavior of the door -"

It's conventional to refer to them as "the Landlords" but I can shed no further light on the matter.