I don't know if it was intentional but they didn't show any children whe it happened. And it really did'nt sound like a normal baby noise, it was all strange like it was backways! And it wasn't only once I heard it, its everytime I see that episode so it must be something. Next time you see it listen out for it, its when she slides down the car and then the scene changes.
Everything that I touch turns to crap, and now... i bring you rain! Hal in 'Flashback'