A system includes a body structure that defines a enclosure, a support system that is located in the enclosure, and a support structure that includes a top portion and an adjustable support assembly. The top portion is located adjacent to the support system, the adjustable support assembly includes actuators, and the adjustable support assembly is configured to move the top portion with respect to the support system. The system also includes sensors that are configured to generate sensor outputs regarding an environment outside of the system, and a controller that detects an event based on the sensor outputs. In response to the detection of the event, the controller outputs a control signal that controls the adjustable support assembly so that the adjustable support assembly moves at least part of the top portion away from the support system.