Originally Posted by Freebase Dali

Do you think it's possible that your brain interpreted an innocuous sound that way? Auditory pareidolia is thought to be an explanation behind hearing words in otherwise unintelligible noise.

I think there was an experiment done, I don't remember all the details, where white noise was modulated in such a way as to create a pattern of unintelligible noise and the listeners would all hear the pattern as a different word or phrase after enough listening to it. The idea behind it is your brain tries to make sense of the data and comes as close as it can to fitting the sound into something it can use.
The idea behind that experiment sort of parallels the way EVP's are recorded and made sense of. Generally the recordings are always of a faint static-like white-noise type of sound that's modulating in some way. That can be achieved simply by someone dragging their foot on concrete for a short period of time and a low quality recorder barely picking it up, or something to that effect.

I'm just throwing ideas out there, but I think it's worth it for you to investigate the physical aspects of what you experienced before investigating the metaphysical ones.