There's not, really, a specific 'old world' that's obvious to Zoriana, but there have been plenty of catastrophes. If Val's telling the truth, what happened to his and Alyssa's world could be about Aroden's death, in which case she definitely has records prior to it. It could be about an asteroid strike on Akiton a thousand years ago that nobody ever mentioned to her. It could be some weird knock-on effect of the death of Curchanus. None of these are actually particularly plausible. It's much more likely that wherever Alyssa and Val's ancestors came from, what happened to it was not a phenomenon so broad that it appeared in the tiny subset of Golarian records she's read.
The description of the entity in some ways suggests something evil. It drives people mad, it feeds on pain, and it seemingly has trouble offering access to positive energy. Val and Alyssa's behavior doesn't. Neither of them seem to be afraid of or even giving unilateral orders to the other, and they've been nothing but kind and helpful to her. Furthermore, if the entity were running a 'keep people in a demiplane and tell them it'll destabilize without pain' sort of scam, it probably wouldn't grant people Plane Shift.
And, also, Val's Teleport and Plane Shift capacity is not great, and Alyssa doesn't really look like she's ever been in a fight. Even if these two are deceiving her, they probably still can't cause too much trouble in somewhere like Cynosure Tower. (Especially since Bevaluu's in town right now. Bevaluu's done some Nidal runs and come back from them, and thus has managed to hit fifth circle before age 40.) They also don't have any magic items or spells active.
All this adds up to her probably wanting to try selling them a teleport from scroll today to Cynosure Tower. Or give them one, but they expressed a willingness to make trade offers and scroll ink isn't cheap.
She rolls a piece of paper. "Scroll." She shows them a scroll case. "Magic scroll." She refocuses on the piece of paper. "Magic." She tears it. "No scroll."
She gets out the raisin and some hardtack again. "Small food. Large food." She gestures to Val. "Val magic large teleport Val Alyssa." She does a quick dimension hop. "Zoriana magic small teleport Zoriana."
She draws a quick sketch of a temple, then adds to it people standing on the ground and clouds in the air and some live plants. "Time time, Zoriana large teleport Val Alyssa Zoriana, Zoriana no want coin. Magic scroll, Zoriana large teleport Val Alyssa Zoriana, no scroll, Zoriana want coin."
Probably they recognized the copper disc as currency? They were talking about trade after she showed it to them.