Copy key to open bolt (6)
I believe the answer is:
escape
'bolt' is the definition.
(I know that bolt has the is a more specific form of the action flee)
'copy key to open' is the wordplay.
'copy' becomes 'ape' (ape can mean to copy or imitate).
'key' becomes 'esc' ('Escape' key on a computer keyboard).
'to open' says to put letters next to each other (some letters go before or 'open' others).
'ape' after 'esc' is 'ESCAPE'.
(Other definitions for escape that I've seen before include "See cap (anag.)" , "Gain freedom" , "Slip away - leak out" , "find way out" , "Get away from the strange EC peas" .)