A pocket slide opening door assembly including a door leaf having a top edge, a door frame assembly, and a sliding assembly for slideable translation of the door leaf in relation to the door frame assembly between a closed position and an open position, wherein the assembly is provided in a plurality of parts for assembly in situ, including in a first part the door leaf, in a second part the door frame assembly with bay or pocket configured to receive the door leaf, or in second and third parts the door frame assembly and separate bay or pocket configured to receive the door leaf, and wherein the door assembly is disposed and configured in manner which prevents ligature about the door leaf top edge and in manner which prevents access to the sliding assembly for tamper purpose or for ligature purpose.