Finished without pax, unfortunately blown up (8)
I believe the answer is:
expanded
'blown up' is the definition.
('expand' can be a synonym of 'blow up')
'finished without pax unfortunately' is the wordplay.
'finished' becomes 'ended' ('ended' can be similar in meaning to 'finished'**).
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'unfortunately' indicates anagramming the letters.
'pax' with letters rearranged gives 'xpa'.
'ended' going around 'xpa' is 'EXPANDED'.
(Other definitions for expanded that I've seen before include "Spread out, enlarged" , "Sort of polystyrene" , "Enlarged, extended" , "Grew larger" , "Grew in extent" .)