An apparatus (10) helps protect an occupant (16) of a vehicle (12). The apparatus (12) includes an inflatable vehicle occupant protection device (14) that is inflatable to help protect the vehicle occupant (16). A vent opening (52) directs flow of inflation fluid away from the protection device (14). A vent member (60) is movable between an open condition enabling flow of inflation fluid away from the protection device (14) through the vent opening (52) and a closed condition at least partially blocking flow of inflation fluid away from the protection device through the vent opening. A panel (80) receives and transfers the force of inflation directed into the protection device to the vent member to urge the vent member toward the closed condition.