Turn to rescue? I have to be devious! (7)
I believe the answer is:
evasive
'devious' is the definition.
(I've seen this before)
'turn to rescue? i have' is the wordplay.
'turn' says the letters should be written backwards.
'to rescue?' becomes 'save' (saving is a kind of rescuing).
'i have' becomes 'I've' (contraction of 'I have').
'save' backwards is 'evas'.
'evas'+'ive'='EVASIVE'
'to be' is the link.
(Other definitions for evasive that I've seen before include "Avoiding giving answers" , "Difficult to pin down" , "Ambiguous" , "Prevaricating" , "Shifty, not giving straight answers" .)