Carnage in service area? (8)
I believe the answer is:
massacre
'carnage' is the definition.
(I know that carnage can be written as massacre)
'service area' is the wordplay.
'service' becomes 'mass' (kind of church service).
'area' becomes 'acre' (an acre is an area of land).
'mass'+'acre'='MASSACRE'
'in' acts as a link.
(Other definitions for massacre that I've seen before include "Slaughter, holocaust" , "The slaughter of many" , "Slaughter of large number of people" , "Mass murder" , "Heavily defeat" .)