I thought about turning Pandora right-side up. This flirtation with logic  and reason ended abruptly.

There is at least one question Pandora's statement raises in regard to past events in the comic, and this question will be at least acknowledged in the next comic. It's entirely possible you have another question that will not be, but hey, at least I'll be vaguely answering one question!

The whole "immortals can hide even from other immortals" dealie is the result of me lookign for a solution to the very simple problem of immortal overlap and how they could possibly not be stepping on each other's toes by now.

I find I like the idea that there can be multiple immortals observing a single event without even noticing each other, and I particularly like that it's linked to them abiding by the rules immortals follow. The more reasons they have to not break those rules, the more credible it is that even someone like Pandora makes due with only bending them.