Lose one's grip and take no further action (4,3,4)

I believe the answer is:

drop the case

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'take no further action' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'lose one's grip' is the wordplay.
'lose' becomes 'drop' (dropping is a kind of losing).
'one' becomes 'the' (both can introduce a definite example of something).
'grip' becomes 'case' (I can't explain this - if you can you should give a lot more credence to this answer).
'drop'+'the'+'case'='DROP THE CASE'

'and' acts as a link.

Can you help me to learn more?

I've seen this clue in The Globe and Mail.

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