I would say its more likely some kind of imagined subconcious response in much the same way that sometimes you can be lying down and suddenly feel like your falling forward (I love that phenomenon I just wish I could replicate it at will).
Its also possible that she was dreaming it and hearing it in the dream caused her to think she was really hearing it.
Quote:2- As an engineer, I would say it's not common, but those things are probable. Sometime, electric device design is really bad, and the device can enter in an undefined state that can cause weird thing to happen.
Yeah its quite freaky people expect machines and computers etc to have behaviour set in stone but odd things do sometimes happen I know I've seen it myself.