Max M:

Your "friend," as well as yourself, needn't have worried. While a little annoying, and perhaps worrying for those who don't know, seepage of air through emergency exits is not particularly uncommon, and not dangerous at all. If you look at the instructions on operating the emergency exit doors, you'll notice that they first have to be pulled inside the plane. At this point, they are usually turned sideways and dumped outside.

However, the cabin of the plane is pressurized, otherwise none of us would survive the trip. The difference between the pressure inside the cabin, and the lack of pressure on the outside, result in a force of several tons pressing on the exit door, keeping it in place. It is also this substantial pressure differential that makes it difficult to maintain a perfect seal around the door, and sometimes causes the hissing sound.

On the ground there would be very little pressure difference, only that resulting from the operation of the air conditioning and ventilation fans. As the aircraft gained altitude however, the inside of the cabin would be maintained at a pressure similar to that on the ground, while the outside pressure would quickly decrease. This is why the the sound increased after the plane took off.

In the end what this means is that it would be physically impossible for the door to be opened while the cabin is pressurized. And if the cabin lost pressure, then there would be no difference between the outside and the inside, resulting in no pressure whatsoever on the door, and no air seepage.

So, as you can see, there was nothing really to worry about. However, the flight attendant, or even one of the cockpit crew, should have explained that to the passengers.

Regards,

Ken Hamer