Cruiser evacuated two islands in emergency (6)
I believe the answer is:
crisis
'emergency' is the definition.
(thesaurus)
'cruiser evacuated two islands' is the wordplay.
'evacuated' suggests removing the centre.
'two' shows that letters should be duplicated.
'islands' becomes 'is' (i is an abbreviation for island).
'cruiser' with its centre removed is 'cr'.
'is' doubled is 'isis'.
'cr'+'isis'='CRISIS'
'in' acts as a link.
(Other definitions for crisis that I've seen before include "A decisive or dangerous time" , "Emergency - decision time" , "Serious or crucial situation" , "Crucial and dangerous moment" , "disaster" .)