The two situations are not the same as noise at the store. A problem with PCS is a messed up and super sensitive startle response. When hubby makes the noise, it causes a startle. When she does it herself, she is expecting the sound and is not startled. It does not depend on the volume of the sound as much as the startle of the sound.

It is an anxiety issue. In my case, it can be called "adrenal cortical hyperfunction." Google it. It can cause a confusion of motor control. Startles while driving can be dangerous as they can cause a mixing of motor control, i.e. brake pedal vs gas pedal.

There are also non-startle sounds that are easier tolerated when the source is understood versus not understood. That odd noise from outside during a windstorm can be anxiety inducing. Going outside to discover what it is can end the anxiety because the brain can now reference the sound . The healthy brain wants to understand the various stimuli around us. Ours are even more sensitive to this need.