Disagreeing the hell out of this. Statistically, the Boyz should have killed three. I've had a squad of Lootas shoot at Terminators, kill three and have an empty Trukk chase them off the board. I've had five Meganobs kill two Terminators. With shooting.
Volume works, if you have enough of it. Your dice are just as likely to roll a 1 as a 6. Siege Shields on Vindicators are seen as practically mandatory.