"I mean I can't claim I love the idea but if someone does show up who can help me I will probably need to do the full disclosure thing and maybe it'll suck less if I practice," he sighs. He finishes whatever's in his mug. "Are you going to stand there with your shield up the whole time, I don't even know what your demonic threat model is here. Though I suppose of course you shouldn't believe me if I tell you it wouldn't help."

"There's plenty of things a shield won't help with, and there's plenty it will. If you haven't enchanted me already, which I haven't ruled out."

"That's not a thing my kinda demon can do. We just make stuff. Well, 'just'."

Shrug. "I figure that either everything you've said is a carefully designed lie, or I don't need to worry about you suddenly attacking me."

"It sounds like you can't help me, and if you don't want any stuff I probably can't help you either, so if you want we could simply not talk."

"What I'd really like is some way to figure out what's going on. Which I guess boils down to some way of knowing whether you're telling the truth or not."

"Well, I certainly can't convince you of that, and it actually sounds extra unpleasant to relate my tragic backstory if you are going to relate to it as a probable malicious lie. You could talk to Bar." He pats it. "She doesn't speak, she does a thing with napkins."

That's potentially a good idea except that she'd have to let the door shut behind her, and also--"As in, napkins appear with writing on them? I could probably tell whether it was you or the bar making them, but I can't actually read whatever language we're speaking right now."

"I'm speaking English and I'm going to wildly guess that you are not. The place has a translation effect. I'm not sure Bar needs it, mind, she might just know all languages in her own right. If you can't read at all I'm not sure if she has a failover."

"Oh, if there's translation magic other than mine going on and it works on text then I'm all set." And that was a helpful, relatively easily verifiable statement. Which would require her to let go of the door to actually verify it.

What is she actually worried about, if she lets go of the door? Number one, that it will shut behind her and she'll be trapped in here with a demon. She's already trapped in here with a demon; the only option she's preserving is the option to make him chase her into the chapel. Which is only a useful option if the bit about the demon not controlling the door and it disappearing if she leaves and closes it is true. Number two, the reduced ability to hear anything going on in the rest of the fort, but if this was a diversion for an attack on the fort the attack would have started already. Number three--actually the previous item was number three and this is number two, if anyone comes looking for her she'll be easier to find like this than if she lets the door close. Probably. 

"Hm. What happens if someone tries to open this door from the other side? Either right now or if it's closed."

"...do you want me to ask Bar for you since you're really attached to standing over there?"

Another little note of confusion in the model where he's lying--he could have just said whatever the lie was without pretending to check. There's no proof of anything either way, but the part of her that's living in the world where he's lying keeps being surprised and confused and the part of her living in the world where he's telling the truth keeps having each new statement slot neatly into place.

"I would like that. Thank you." Possibly nobody will realize she isn't with someone else until her patrol shift, which is inconveniently not for several more hours, but surely at that point they'll raise the alarm.

He shrugs - his wings ripple a little - and he turns to the bar. "Hey Bar, while she's holding the door open what happens if someone tries to open that door in her world from the other side?"

A napkin appears.

He picks it up to read. "It won't open, if they try to destroy it Bar's not sure what happens because she's really really old and that doesn't happen often enough to be in her window of clear recollection and it might not be consistent anyway, you and them might be able to holler a conversation insofar as you'd be audible to each other if you were standing on opposite sides of the closed door," he reports.

That sounds like the sort of thing that could happen. There are other things that would sound almost as much like the sort of thing that could happen and would be a lot more useful for most possible schemes. Going in would still be doing something she has reason to believe a powerful demon wants her to do.

Ultimately the thing that decides her is that, if the bar is in fact a person, they might need help and she might be able to help. She takes a step into the room, lets the door close behind her, and starts walking towards the bar. 

And then spins around at maximum speed and yanks the door open again, for just long enough to make sure it didn't seal behind her or start opening onto the Abyss or anything, and then approaches the bar for real.

The demon observes this with a sort of glum unimpressedness.

Welcome to Milliways. Can I get you a drink? The first one's free.

Neither the bar nor the demon reacts when she gets within twenty feet, so most likely neither of them is possessed or an Evil summon.

"I'm going to cast Detect Magic, all it does it let me see spells being cast," she says, because having a divination mistaken for a combat spell by a demon unfamiliar with Golarion's magic would be the stupidest way for this to turn into a fight. If this draws no objections, she casts it, then turns to the bar and says, "Not right now, thank you. Can you tell me about the nature of this place? Where it came from, why and how it moves, what sort of people inhabit it?"

THE BAR IS REALLY MAGIC

THE DEMON IS TOO

I'm afraid I can't remember anything quite so subjectively long ago as all that. The establishment itself is stationary and the door, which connects many worlds, seems at times to have "whims" and "moods", but not ones I can get to know by anything other than observation. Sometimes people stay here for extended periods for one reason or another, such as the giant squid in the lake in the backyard, though because of the time dilation effect between mutually unobserved areas there could easily be thousands of years passing for someone down here while a patron in their room upstairs experienced only an eyeblink.

Ow ouch her whatever Detect Magic uses instead of eyes. She was at least able to determine that the appearance of the napkin originated with the bar, not the demon, before she loses the spell.

". . . Does time dilation mean if I go back out the door it might be hundreds of years from now? What happens if the door doesn't exist any more?" This was not in her threat model and it should have been, fae do that sort of thing so there's no reason demons couldn't.

Almost always, while the door is not open to a particular world and someone from it is in Milliways, time will not pass in that world.

Well, if she believes the bar, which is definitely powerful enough to have an alignment aura and doesn't ping as Evil but either of those can theoretically be spoofed, about the time dilation at all, there's no reason to disbelieve it about it working that way with the door. She goes and checks the door again anyway; it still opens on a chapel that looks exactly the same as it used to look.

"And you've been here, and been a, a wooden structure, for as long as you can remember? How long has the demon been here?" She considers asking the demon his name and then realizes she was just thinking about not having fae magic her threat model, and fae are one of the few kinds of being who might falsely claim to be a demon.