Character from Porridge breaks into vault which ends in trouble (5)
I believe the answer is:
ethos
'character' is the definition.
(moral character)
'porridge breaks into vault which ends in trouble' is the wordplay.
'ends' says to take the final letters.
'in trouble' is an anagram indicator.
The final letters of 'porridge breaks into vault which' are 'esoth'.
'esoth' anagrammed gives 'ETHOS'.
'from' acts as a link.
(Other definitions for ethos that I've seen before include "Characteristic spirit of a community - for those" , "Cultural spirit" , "The distinctive spirit of a culture or an era" , "Characteristic spirit (of, eg, a culture)" , "moral code" .)