Sounds to me like she"s a little loopy, but at the same time it"s within the realm of possibility that she"s just really sensitive to certain sound frequencies. For example, most CRT"s make a very very very high pitched buzzing sound that I can hear, but few others can. It"s more or less noticeable depending on the CRT, some are very noticeable, some I can"t hear at all. I"m in on the second floor of our two storey office, and I can clearly hear one of the project manager"s monitors downstairs whenever he turns it on. There"s an open stairwell so sound transmits fairly easily, but I certainly can"t hear a normal conversation taking place in his office. I don"t get annoyed or distracted by the sound, but if I stop and listen for it, it"s definitely there.
But overall yeah, I"d say the bitch is just plain crazy.
However, a couple questions:
1/ What kind of building is this? How many floors, how many units per floor?
2/ What is the construction of the building? Stick frame, concrete, masonry?
3/ How are the suites heated/cooled? Hot water baseboard? Gas/electric/hot water furnace/fancoil?
4/ Are the hallways served by some sort of make-up air system? Not sure what the building codes are like where you are, but typically any building has to have some source of fresh air constantly filling the building, to keep it positive compared to the air pressure outside.