Needle; insinuate (3,2)
I believe the answer is:
get at
I believe this is a double definition.
'needle' is the first definition.
(I know that needle is a kind of beset)
'insinuate' is the second definition.
(I've seen this in another clue)
(Other definitions for get at that I've seen before include "Criticise (someone)" , "Reach - mean - attack verbally" , "Pick on - gain access to" , "Unfairly influence" , "Nobble; gain access to" .)