Ate fast, secured door and ran off (6)
I believe the answer is:
bolted
I believe this clue is a quadruple definition!!
'ate' is the first definition.
(bolting is a kind of eating)
'fast' is the second definition.
(synonyms)
'secured door' is the third definition.
(a door may be secured by a bolt)
'and' acts as a link.
'ran off' is the fourth definition.
('bolt' can be a synonym of 'run off')
(Other definitions for bolted that I've seen before include "Ran away" , "Fastened door with sliding bar (6)" , "Absconded" , "Fled, having locked up?" .)