The only context variable that the On Flie Clicked event provides is “doc”. I would suggest placing a debugger; statement in the On File Clicked event to pause execution when the even is fired and explore the properties of the object in the console.
However, you may wish to try getting a reference to the underlying Service Data Table. Keep in mind, this naming convention is subject to change at any time. (ie: /BPM_Document_List1/BPMFileList/DocList) Then, use .getData() to retrieve the properties. For instance, .getData().items.