This isn't the storage room.

It is, instead, a...restaurant of some kind? The back wall is all windows, and on the other side of the windows is outer space. The stars are not Equestria's familiar stars either. An unexpectedly large number of them are currently exploding.

"Um...where am I?" she says aloud. "Is anypony here?"

There is not currently anyone else there. However, a napkin appears on the bar, on which is written:

Welcome to Milliways, the restaurant at the end of the universe! The first drink is free.

That doesn't really answer any of her questions. Really, it just generates a lot more.

Milliways is an interdimensional bar accessible from a large number of different universes. Time in a given universe does not pass while a patron therefrom is inside with the door closed. Food, beverages, and books from any of the universes from which Milliways is accessible are available for purchase. I can accept almost anything of value in exchange for purchases but you do have to pay somehow.

Violence against other patrons is strictly forbidden in the main bar area. Security will be enforced by categorically adequate means.

Holy shit this is so cool!!!

She will continue to quiz the bar on the finer details of how the hay any of this works, and receive mostly unsatisfactory answers, until another patron arrives.

In walks a much larger equine in an exotic brown.

Brown isn't that exotic a color! Dr. Whooves is brown—that said, she's not entirely sure that Dr. Whooves isn't himself an alien. Mostly, her reaction is 'aaah why is she so big' and 'what happened to her face'.

Katixa will see a pastel purple winged unicorn about three feet high at the shoulder, reading a book and drinking from a teacup that she's levitating in front of her face. Compared to the animal that some other places call a 'horse', she has a much larger cranium and shorter snout, with large, relatively forward-facing eyes. Her mane and tail are multicolored and there's a design apparently dyed into both of her flanks.

"Oh, hi!" she says to the new arrival, suddenly looking up from her book. "I'm Twilight Sparkle, Princess of Friendship. What's your name?"

Katixa can speak, in Milliways, due to the translation effect being willing to convert whuffling noises and nickers that she means something verbal by into words for her!

Katixa doesn't know that, though! She inspects the levitating teacup curiously and doesn't say anything.

(The Equestrian language actually consists mostly of phonemes that Katixa could in theory produce, but it's not familiar to her, and if the translation effect is causing her to hear, say, Taldane, then she may not realize that she can reply.)

... oh, right, the alien doesn't speak Equestrian. Why would she? Still, one wonders how the bar does, so it's worth testing. "Tap your hoof twice if you can understand me but not reply," she says.

She offers Katixa the teacup. It's full of tea, though probably too small for her to drink from without spilling the entire thing.

Tap tap! Katixa can drink reasonably delicately from open vessels. A teacup is a challenge and she spills a little, but not all of it.

Actually, wait, this is an alien, there are more basic things she ought to be checking. "Tap once for yes and twice for no—does your species normally communicate with language?"

Tap tap. Her species is "horse"; Katixa is just a special example of the species.

... rather than try to figure this out via hoof-taps, Twilight is just going to ask the bar what species Katixa is and how she normally communicates.

In Milliways, she can talk if she tries!

"Um, anyway, this place is called Milliways and apparently it connects to a large number of different universes," she tells Katixa. "The bar is intelligent and you can ask it for things; it says that in here, you can talk if you try. There's translation magic active, or else you wouldn't be able to understand me."

"...I can talk?" says Katixa. "...I can talk! Can I get my paladin and talk to him?"

"If you leave and let the door close behind you, you probably won't be able to get back in. I can hold the door for you, I guess?"

"I also don't know what a 'paladin' is but I'm willing to be shown rather than told."

"Well he's not right where I was. He's doing important government things. A paladin's a holy warrior but right now there is not fighting and there is government so he's doing that."

"I'm glad there's no fighting! I'm technically a Princess but I haven't been one very long and the older Princesses do most of the actual governing. I suppose that talking to aliens probably would be one of my royal duties, although I found this place quite by accident and didn't intend to meet any aliens when I woke up this morning." It's probably not in Celestia's power to create an interdimensional bar but she absolutely would arrange the whole thing just as it's happened if it were.

"Uh, what's your name, by the way?"

"I'm Katixa!"