Killing a service area (8)
I believe the answer is:
massacre
'killing' is the definition.
(massacre is a kind of killing)
'a service area' is the wordplay.
'a service' becomes 'mass' (I've seen this before).
'area' becomes 'acre' (I've seen this before).
'mass'+'acre'='MASSACRE'
(Other definitions for massacre that I've seen before include "Indiscriminate killing of large numbers" , "Wanton slaughter" , "Heavily defeat" , "Butchery" , "Murder (of many persons)" .)