OK, so I just discovered that my downstairs neighbor (whom I also didn’t know) has moved out, too…and he/she/them/it were only here for a couple of months.
I think it’s pretty obvious that this is all entirely personal. The only person left who’s within screaming-distance, should I be blugeoned, is my previous next-door neighbor’s donwstairs neighbor (otherwise known as my previous donwstairs neighbor’s next-door neighbor)…and, no, I don’t know her, either.
I’m screwed.