Siren goes off by small exits (10)

I believe the answer is:

egressions

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'exits' is the definition.
The answer and definition can be both acts as well as being plural nouns.
Maybe you can see an association between them that I don't see?

'siren goes off by small' is the wordplay.
'off' is an anagram indicator.
'by' is a charade indicator (letters next to each other).
'small' becomes 's' (abbreviation - e.g. clothes size).
'siren'+'goes'='sirengoes'
'sirengoes' is an anagram of 'egression'.
'egression'+'s'='EGRESSIONS'

Can you help me to learn more?

I've seen this clue in The Times and The Sunday Times.

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