The present invention provides an aircraft passenger accommodation unit comprising a seat, a shell that allows a passenger egress between an aisle and the seat through an opening, and a door assembly comprising a door slidable with respect to the shell between a retracted position and an extended position, a slide track attached to the shell, a slide runner for sliding along the slide track, and a connection mechanism for selectively connecting the door to the slide runner, wherein the door has a first sliding mode in which the connection mechanism connects the door to the slide runner and wherein the slide runner slides along the slide track, and a second sliding mode in which the connection mechanism does not connect the door to the slide runner and wherein the door slides in relation to the slide track. The invention also provides a door arrangement and associated methods.