Rush to get an instrument (4)
I believe the answer is:
reed
I believe this is a double definition.
'rush' is the first definition.
(I've seen this before)
'an instrument' is the second definition.
(reed is a kind of instrument)
'to get' acts as a link.
(Other definitions for reed that I've seen before include "Tall grass that grows in swamps" , "Film director" , "Tall grass at water's edge" , "Blade of tall marsh grass" , "Rush" .)