Get out of Dodge (4)
'get out of dodge' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for flee that I've seen before include "retreat" , "Leave" , "head for the hills" , "Take to one's heels" , "Take flight" .)
(Other definitions for alive that I've seen before include "Still with us" , "Still kicking, say" , "Still in use, not dead" , "Animated and kicking" , "Extant" .)