Realise that you have to stop and get very cross (3,3)
I believe the answer is:
see red
'get very cross' is the definition.
(to see red is to get angry)
'realise that you have to stop' is the wordplay.
I cannot really understand how this works, but
'realise' could be 'see' (synonyms) and 'see' is located in the answer.
The remaining letters 'red' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'and' acts as a link.
(Other definitions for see red that I've seen before include "Lose temper colourfully, as bull does (3.3)" , "get angry" , "Lose temper like raging bull" , "Lose temper as bull might" , "Become enraged" .)