Humans relying on replacement of outsiders with qualified doctor (7)
I believe the answer is:
mankind
'replacement of outsiders with qualified doctor' is the definition.
I can't judge whether this defines the answer.
'humans relying' is the wordplay.
'humans' becomes 'man' (man can mean humanity as a whole).
'relying' becomes 'kind' (I can't explain this - if you can you should believe this answer much more).
'man'+'kind'='MANKIND'
'on' is the link.
Can you help me to learn more?
(Other definitions for mankind that I've seen before include "Human race" , "Human beings collectively" , "people, in general" , "all of us" , "People generally" .)