Escape student in brawl (6)
I believe the answer is:
flight
'escape' is the definition.
(I know that escape can be written as flight)
'student in brawl' is the wordplay.
'student' becomes 'l' (as in L-plates for learner drivers).
'in' indicates putting letters inside.
'brawl' becomes 'fight' (I've seen this before).
'l' going inside 'fight' is 'FLIGHT'.
(Other definitions for flight that I've seen before include "Stairs; escape" , "Group of birds - running away" , "A series of stairs" , "Trip by air" , "Set of stairs" .)