It's not certain the doctor will come in the storm (6)
I believe the answer is:
gamble
'it's not certain' is the definition.
I can't tell whether this definition defines the answer.
'doctor will come in the storm' is the wordplay.
'doctor' becomes 'MB' (Bachelor of Medicine, Medicinae Baccalaureus).
'will come in' is an insertion indicator.
'the storm' becomes 'gale' (a gale is a windy storm).
'mb' going inside 'gale' is 'GAMBLE'.
'the' acts as a link.
Can you help me to learn more?
(Other definitions for gamble that I've seen before include "Wager or bet" , "Bet -- Procter's partner" , "Bet; risky undertaking" , "Run a risk" , "punt" .)