Try again to get out of fire door (4)
I believe the answer is:
redo
'try again' is the definition.
(to attempt or do again)
'out of fire door' is the wordplay.
'out of' indicates the answer is hidden within the clue.
'REDO' can be found hidden inside 'fire door'.
'to get' is the link.
(Other definitions for redo that I've seen before include "Perform (action) again" , "further attempt?" , "Create again" , "Fashion again" , "Start again" .)