Erratic pulse in queues (5,2)
I believe the answer is:
lines up
'queues' is the definition.
('line up' can be a synonym of 'queue')
'erratic pulse in' is the wordplay.
'erratic' indicates anagramming the letters.
'pulse'+'in'='pulsein'
'pulsein' is an anagram of 'LINES UP'.
(Other definitions for lines up that I've seen before include "Queues" , "Forms queue" , "seen on washing days?" .)