Train one to interrupt (5,2)
I believe the answer is:
break in
I believe this is a double definition.
'train' is the first definition.
(thesaurus)
'one to interrupt' is the second definition.
(I've seen this in another clue)
(Other definitions for break in that I've seen before include "Enter forcibly" , "Illegally enter" , "Criminal entry" , "Domesticate" , "Forced entry" .)