Very unconventional means of escape (3,3)
I believe the answer is:
way out
This clue is a double definition.
'very unconventional' is the first definition.
(way out can mean unconventional or strange)
'means of escape' is the second definition.
(a way out is a way of escaping)
(Other definitions for way out that I've seen before include "Extremely unconventional" , "Exit - eccentric" , "Exit - weird" , "Unconventional - exit" , "Hit wicket, for example" .)