Evacuation Valves
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2013 Volvo C70, 2012 Volvo C70, 2011 Volvo C70, 2010 Volvo C70, and 2009 Volvo C70. However, it is still accessible from the selected car via links, so may be relevant.
In 4-door vehicles, the air vents are located at the edge between the parcel shelf and the rear windshield. The air goes from here through the cargo compartment and on out through the air vents behind the rear bumper. In 5-door vehicles, the air passes directly out through the air vents in the cargo compartment.
There are rubber flaps in the air vents. The flaps open when the air pressure is slightly higher in the passenger compartment that outside. When the air pressure is the same on the inside and the outside, the flaps close. This prevents water from penetrating.