Run amok and barge into errand boy (7)
I believe the answer is:
rampage
'run amok' is the definition.
(I've seen this before)
'barge into errand boy' is the wordplay.
'barge into' becomes 'ram' (I've seen this in another clue).
'errand boy' becomes 'page' (page is a kind of errand boy).
'ram'+'page'='RAMPAGE'
'and' acts as a link.
(Other definitions for rampage that I've seen before include "Violent action" , "Uncontrolled rush" , "Violent rush" , "Rush about wildly in par game" , "Rush around violently and uncontrollably" .)