It is generally considered out of line to interrupt anyone who has been recognized and is posing a question to an interviewee.    It is not considered to be out of line to interrupt an interviewee, though one's manner may be questioned, during an answer.     The issue with the Senator appears to be that other Senators on the panel were interrupting, and disrupting, her questions during her allotted time.
 
That's todays answer from Uncle Crotchety.