Medic performing easy work off the record (9)
I believe the answer is:
moonlight
'work off the record' is the definition.
(to moonlight is to do a secret second job)
'medic performing easy' is the wordplay.
'medic' becomes 'mo' (medical officer).
'performing' becomes 'on' (as in being on stage).
'easy' becomes 'light' (similar in meaning).
'mo'+'on'+'light'='MOONLIGHT'
(Other definitions for moonlight that I've seen before include "work illegally" , "Lunar rays seen in thin gloom" , "Burn the midnight oil" , "Secretly work" , "Natural (and romantic?) illumination" .)