Advanced examination incomplete in chambers (5)
I believe the answer is:
atria
'chambers' is the definition.
(atrium is a kind of chamber)
'advanced examination incomplete' is the wordplay.
'advanced' becomes 'a'.
'examination' becomes 'trial' (I've seen this before).
'incomplete' means to remove the last letter.
'trial' with its last letter removed is 'tria'.
'a'+'tria'='ATRIA'
'in' is the link.
(Other definitions for atria that I've seen before include "Central areas in buildings; open to the sky" , "Covered courts" , "Upper chambers of the heart" , "Public spaces with galleries" , "Open courts of Roman houses" .)