Proving to be a bouncer? (7,3)

I believe the answer is:

turning out

I'm a little stuck... Click here to teach me more about this clue!

'proving' is the definition.
('turn out' can be a synonym of 'prove')

'be a bouncer?' is the wordplay.
I cannot really understand how this works, but
'be' could be 'go' (going is a kind of being) and 'go' is found in the answer.
This explanation may well be incorrect...

'to' is the link.

Can you help me to learn more?

I've seen this clue in the Evening Standard.

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