Perish, taking a route south of col (4,4)
I believe the answer is:
pass away
'perish' is the definition.
('pass away' can be a synonym of 'perish')
'a route south of col' is the wordplay.
'route' becomes 'way' (way is a kind of route).
'south of' is a charade indicator (letters next to each other).
'col' becomes 'pass' (I've seen this before).
'a'+'way'='away'
'away' after 'pass' is 'PASS AWAY'.
'taking' acts as a link.
(Other definitions for pass away that I've seen before include "disappear" , "Perish" , "Die" .)