An apparatus includes a housing, a carrier, and an expandable assembly. The housing defines an opening configured to selectively place a gas chamber of the housing in fluid communication with an exterior volume. The carrier is movably disposed within the housing and is coupled to a medicament container. A proximal surface of the carrier defines a portion of a boundary of the gas chamber. The expandable assembly has a first member and a second member. The first member is coupled to an elastomeric member disposed within the medicament container, and the second member includes a valve portion. The expandable assembly transitions from a collapsed configuration to an expanded configuration when the elastomeric member moves within the medicament container. The valve portion moves relative to the opening when the expandable assembly transitions from the first to the second configuration, placing the gas chamber in fluid communication with the exterior volume.
