Bolt and key to copy (6)
I believe the answer is:
escape
'bolt' is the definition.
(I know that bolt is a more specific form of the action flee)
'key to copy' is the wordplay.
'key' becomes 'esc' ('Escape' key on a computer keyboard).
'to copy' becomes 'ape' (ape can mean to copy or imitate).
'esc'+'ape'='ESCAPE'
'and' acts as a link.
(Other definitions for escape that I've seen before include "Break loose - flight" , "Elude, dodge" , "Get away from depravity" , "Get away from confinement" , "Get out of captivity, go over the wall" .)