At first, I tried to think it was just a prank, but this is the setup when that weird experience happened:
- room has only one entrance and exit, with two empty beds and an empty toilet (I checked).
- The only other aide beside me is a black dude working at the opposite wing. The nurse is at her station, doing endless paperwork.
- When I heard the voice that said "Hello", I instinctively turned to the source of the sound which is a blank wall between the two beds.
That's all there is to it. It boggled my mind a bit, but as I said before, its not scary.