Perhaps seniors arranged departure (9)

I believe the answer is:

egression

'departure' is the definition.
(thesaurus)

'perhaps seniors arranged' is the wordplay.
'perhaps' becomes 'eg' (for example).
'arranged' is an anagram indicator (letters rearranged).
'seniors' is an anagram of 'ression'.
'eg'+'ression'='EGRESSION'

(Another definition for egression that I've seen is " Emergence".)

I've seen this clue in The Independent.

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