Deadly apartment collapsed (4,4)

I believe the answer is:

fell flat

'collapsed' is the definition.
(I've seen this before)

'deadly apartment' is the wordplay.
'deadly' becomes 'fell' (I've seen this before).
'apartment' becomes 'flat' (synonyms).
'fell'+'flat'='FELL FLAT'

(Other definitions for fell flat that I've seen before include "failed to impress" , "collapsed" , "provoked no interest" .)

I've seen this clue in The Daily Express.

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