An apparatus (10) includes an inflatable vehicle occupant protection device (14) that includes a first panel (160) with at least one first vent opening (142). A second panel (144) secured to the first panel (160) includes a base portion (150) and a door portion (156). The base portion (150) includes at least one second vent opening (200) and is folded to position the door portion (156) between the first panel (160) and the base portion (150). The door portion (156) has an open condition positioned away from the vent openings (142, 200) permitting inflation fluid to vent through the vent openings. The door portion (156) has a closed condition positioned between the first and second vent openings (142, 200) blocking inflation fluid from venting through the first and second vent openings. The door portion (156) is movable to the closed condition when the protection device (14) deploys. The door portion (156) has a generally triangular configuration with a base merging with the base portion (150) of the door panel (144) and first and second edge portions (264) that extend away from the base and converge at a terminal end (224) of the door portion.