Be careful how a cut possibly throbs initially (5,3)

I believe the answer is:

watch out

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'be careful' is the definition.
I can't tell whether this definition defines the answer.

'how a cut possibly throbs initially' is the wordplay.
'possibly' indicates anagramming the letters.
'initially' indicates taking the first letters.
The initial letter of 'throbs' is 't'.
'how'+'a'+'cut'='howacut'
'howacut' is an anagram of 'watchou'.
'watchou'+'t'='WATCH-OUT'

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(Other definitions for watch out that I've seen before include "this could make synchronisation difficult!" , "Be vigilant" , "Be careful!" .)

I've seen this clue in The Times.

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