Move strongly ahead, maybe in the theatre (7)
I believe the answer is:
surgeon
'maybe in the theatre' is the definition.
I can't tell whether this defines the answer.
'move strongly ahead' is the wordplay.
'move strongly' becomes 'surge' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ahead' becomes 'on' (synonyms).
'surge'+'on'='SURGEON'
Can you help me to learn more?
(Other definitions for surgeon that I've seen before include "Performer of operations" , "Medical man" , "Ship's doctor" , "Doctor with a scalpel" , "One operating in theatre" .)