C-Max whooshing noise when tapping the brakes quickly.

What is your question?

I just purchased a 2013 C-Max Energi and had a question. The car came with a 100 day warranty and I am not sure if I have a problem or not. There is a $50 deductible and would hate to throw it away if there is nothing wrong with the car. The car has 27K and is very clean. I noticed a whooshing sound when I quickly applied the brakes today (think of a brake check where you quickly tap the brakes). It was a quick whoosh as if air was being released. I can recreate the issue but it does not happen under normal braking. I've had the car for a week and this is the first time I've heard it. Is this normal? Any help would be greatly appreciated.