I wrote a short little something about lictors here. Lictors didn't really do anything in particular, their job was to follow around the magistrate that they served all day. That was pretty much it. Lictors were not the only people who followed a magistrate around--there was an entire retinue of attendants, most of whom were clerks and messengers. The lictors may have in origin have been bodyguards, but that wasn't really their duty at all by Caesar's time--the very fact that they were supposed to march along in front of the magistrate in single file sort of shoots any serious attempt to guard the magistrate's life in the foot--all you needed to do was approach him from the rear. Lictors were symbolic--their appointment to a magistrate's staff was not important because the magistrate needed to use them as a bodyguard, but because they had symbolic significance--only magistrates holding imperium had lictors, and the procession of lictors served to announce such a magistrate's approach. Without lictors nobody could legally hold the magistrate's fasces. Legally, without fasces, there was no imperium. It was purely ceremonial--the most that lictors might have been able to do if they were in the Theater of Pompey that day is try to get in the way of the conspirators, but one wonders why Caesar would intentionally antagonize his opponents by not dismissing his dictatorial lictors (the only people who could retain lictors for life were the kings--yet as Dictator for Life Caesar now held this privilege, and like the kings he, as a dictator, could keep his lictors at arms within the city). We don't know of a single instance of lictors actually acting as proper bodyguards, saving a magistrate's life from some peril. We do know that they would clear the way for the magistrate, if there was a crowd in front of him, and that they would stand beside him in the forum. But that doesn't mean very much at all