Doctor going to work in shed (4)
I believe the answer is:
drop
'shed' is the definition.
(to shed is to cast off or drop)
'doctor going to work' is the wordplay.
'doctor' becomes 'dr' (abbreviation).
'going to' is a charade indicator (letters next to each other).
'work' becomes 'op' (short for opus).
'dr'+'op'='DROP'
'in' acts as a link.
(Other definitions for drop that I've seen before include "A little medicine" , "Fall down with liquid globule" , "Fall down after prod" , "Desert" , "shed" .)