Hasten to get out of Galashiels (3)
I believe the answer is:
hie
'hasten' is the definition.
(I know that hasten can be written as hie)
'out of galashiels' is the wordplay.
'out of' indicates a hidden word.
'HIE' is hidden in the letters of 'galashiels'.
'to get' is the link.
(Other definitions for hie that I've seen before include "Be quick (lit.)" , "make haste" , "Make one's way quickly" , "Hasten" , "Hurry" .)