Quickly leave launch strip (4,3)
I believe the answer is:
take off
I believe this clue is a triple definition!
'quickly leave' is the first definition.
(to take off is to leave somewhere quickly)
'launch' is the second definition.
(I've seen this before)
'strip' is the third definition.
(taking off is a kind of stripping)
(Other definitions for take off that I've seen before include "Remove clothes or become airborne" , "Doff" , "become successful" , "Launch" , "Make it" .)