Trouble the medical officer, just in case (6)
I believe the answer is:
molest
'trouble' is the definition.
(both can mean to bother or harass)
'medical officer just in case' is the wordplay.
'medical officer' becomes 'MO' (abbreviation).
'just in case' becomes 'lest' (I've seen this in another clue).
'mo'+'lest'='MOLEST'
'the' acts as a link.
(Other definitions for molest that I've seen before include "Harass" , "badger" , "Accost or pester" , "Fame" , "Pester; assault" .)