Key copier, one getting away? (7)
I believe the answer is:
escaper
'one getting away?' is the definition.
(someone making an escape)
'key copier' is the wordplay.
'key' becomes 'esc' ('Escape' key on a computer keyboard).
'copier' becomes 'aper' (ape can mean to copy or imitate).
'esc'+'aper'='ESCAPER'
(Other definitions for escaper that I've seen before include "One runs away" , "One making a getaway" , "One who gets away" , "Fugitive" , "it's no longer caged" .)