Most of those people look, after drunk nurses start to dance (4,3,5)
I believe the answer is:
take the floor
'start to dance' is the definition.
(I've seen this before)
'most of those people look after drunk nurses' is the wordplay.
'most of' means to remove the last letter.
'those people' becomes 'them' ('they' refers to a group of people).
'drunk' indicates an anagram.
'nurses' is an insertion indicator (nurse can mean to hold onto or harbour).
'them' with its last letter removed is 'the'.
'look'+'after'='lookafter'
'lookafter' is an anagram of 'takefloor'.
'the' placed into 'takefloor' is 'TAKE THE FLOOR'.
(Other definitions for take the floor that I've seen before include "Stand up to dance or to make a speech" , "Rise in order to make a speech or motion" , "Rise to address a meeting" , "Start dancing" , "Rise to speak" .)