that is a common issue with many vehicles, not specific to the Escape, it is called "helicoptering" due to the sound being similar to a helicopter sound. Caused by air rushing into the car and air pressure not being able to release, if you open a front window slightly or alter the position of the open windows the air pressure can adjust. It can happen on any vehicle with windows open in certain situations. Sometimes it can happen with the sunroof open and one rear window, or a mix of different window positions, every vehicle is slightly different. The noise is very bothersome and I hate when it happens, but I just alter some of the window positions and it can be eliminated. | 
