Leave vehicle burning (6)
I believe the answer is:
This clue is a double definition.
'leave vehicle' is the first definition.
(eg alight can mean to disembark from a train)
'burning' is the second definition.
(Other definitions for alight that I've seen before include "Descend from vehicle" , "Disembark; on fire" , "Get out of train" , "Come to rest, settle" , "Step off the bus because it's on fire?" .)