Reach crisis point (4,2,1,4)
I believe the answer is:
come to a head
'reach crisis point' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for come to a head that I've seen before include "arrive at a crisis" , "Reach a critical stage" , "Reach a climax" , "Reach crisis point" , "arrive in critical condition" .)