This seems to be another option here (not too sure, though).

See, for example,

http://www.hopkinsmedicine.org/jhhr/PoliciesProcedures/HR201...
("All Functional Units should implement an Employee Access System and request/review Form similar to the JHHSC/JHH’s Central Employee Records Procedures.")

http://www.wbdg.org/design/hospital.php
("Hospitals are the most complex of building types. Each hospital is comprised of a wide range of services and functional units. These include diagnostic and treatment functions, such as clinical laboratories, imaging, emergency rooms, and surgery; hospitality functions, such as food service and housekeeping; and the fundamental inpatient care or bed-related function.")

"off-ward duty" might be just as appropriate, though.