"I am not a domain expert on Golarion, but. If I try to come at this from a dath ilani angle. We can probably premise, more strongly than we can premise almost any other part of this, that the timing between my stepping outside, and the attack, was not coincidental. It's to within - something like one in five hundred parts of the day, or less, for it to be a coincidence that tight is something we'd see only out of one in five hundred times."
"We then have a classic probability-theoretic detective story, that of accounting for coincidence: in particular, a coincidence of timing."
"Suppose that, prophecy being broken, we don't believe that any god managed to time it in advance by sheer manipulation of coincidence. We furthermore believe Nidal didn't see me stepping outside, because they didn't know where I'd be."
"Then some other element of the sequence of events that led to me being outside, must have triggered the attack, or been timed with the attack."
"Furthermore, though more tentatively, at least one element in this sequence of events was chosen by an adversary of Nidal, because they plausibly would've gotten me inside my bedroom otherwise."
"This causal sequence started with my asking to cast my cleric spells - no, it started with Carissa returning from her shopping trip at the exact time she did. It ended when I summoned the archon. But I doubt Carissa should be looking for anything that timed the end of her shopping trip, because she had dinner after that, and with prophecy broken, you won't get two-minute timing at the end of a causal sequence like that."
"Something in that causal sequence either triggered the attack, or was triggered by it."