ABM risked being set alight (9)
I believe the answer is:
disembark
'alight' is the definition.
(thesaurus)
'abm risked being set' is the wordplay.
'being set' is an anagram indicator (instruction to set the letters).
'abm'+'risked'='abmrisked'
'abmrisked' is an anagram of 'DISEMBARK'.
(Other definitions for disembark that I've seen before include "Get off" , "Go ashore" , "Step on dry land" , "to set oneself apart from trader, say" .)