An unattended and apparently unstocked tavern sort of place with exploding stars out the window.

"Okay look whoever's doing this, I have a meeting in twenty minutes, I have never been late to a meeting and this is not going to be the first time, what do you want and why could it not be achieved by emailing me."

A napkin appears on the surface of the bar.

...she walks over to the bar to look at the napkin.

Welcome to Milliways. The door is controlled by forces beyond my influence but if it behaves as typical you will find that time in your world is paused while you are inside and it is closed, and should you depart and close the door and reopen it again, whatever normally lies beyond will be restored to its usual place.

She raises an eyebrow, then promptly turns around, walks to the door, opens it, drops a pen, but closes the door before it's finished falling. She counts to five then opens the door again.

The pen finishes falling.

How interesting. She collects the pen and returns to the bar. "And you say this place will have disappeared should I walk out that door and let it close?"

Yes, unless someone else from your world enters, in which case time will not pass for you in your world while the door is closed but the establishment will remain accessible via that door.

"I see. And you said the door is beyond your control; is it controlled by whoever it is you work for? And who do you work for?"

'Whoever controls the door' is typically glossed as 'the landlords'. I do in a sense work for them but I have no way to communicate with them except insofar as they may be presumed to watch certain events such as hiring.

"They presumably hired you? And are you—incorporeal, or just invisible?"

Neither. I am the bar. Please call me Bar. I'm afraid I can't remember beginning, even if that is a thing that once happened.

She nods. "It's a pleasure to meet you, Bar. I'm Abigail. Are the landlords devils or am I still underestimating how unusual my day has gotten?"

I don't have any specifics on what if any species they may identify with. If you mean connotationally, they are, I think, not.

"No, I was being somewhat specific about species. So what exactly is this place, is there a general introduction?"

The establishment is named Milliways. The first drink is free and thereafter I charge reasonable currency-dependent prices for medium-sized nonmagical nonliving nonweapon objects, though you may choose to run up a tab. There is a backyard and rooms available to rent upstairs. The bathroom, infirmary, and security office are accessible from the hall to your right. In the main bar area, violence and nudity are forbidden. Parts of the establishment that are not interacting with one another may experience relative time dilation. There is a giant squid in the lake.

At which point the door opens and another woman stalks in, very focused on the tablet in her hand, she turns to her left, takes ten precise steps, pulls a headset off one ear (spitting a curse) and dropping it onto...

"...Damnit, I thought I talked him out of rearranging the office," she sighs, crouching down to pick up her headset from the floor. As she straightens, she catches sight of Abigail. "I am fairly certain you don't work for us." She looks around the room. "And I definitely talked him out of putting a bar into the office."

Abigail looks up from her napkin reading at the newcomer. "I'm afraid you may have made the same mistake I did. This place apparently steals doors from—was it worlds you said?" she says, directing that last part to Bar.

Yes, although it is not unheard of for two locations in the same world to have doors at the same time if the time pausing feature is not behaving as typical.

"It apparently temporarily steals doors, often but not always from different worlds, and while you're here time is often but not always paused where you came from. Should you leave, the door that led here will once again behave as normal."

"Fascinating," she clips her headset onto her collar for now. "Which suggests that there are universes outwith the separate dimensions we are already capable of accessing. Although the technology to manipulate time at that level...quite impressive. And to temporarily steal doors...well."

"It's... unlikely to be through technology that this place does such things." She looks at the bar. "Is it?"

Not to the best of my knowledge.

Back to the newcomer: "Not technology," she repeats. "—for the record, the Bar is sentient and speaks through napkins. And this place is called Milliways. There are a few other details on the napkins here."