How can a non-soldier Shepard defeat the Harbinger on the Collector ship quickly?

In Mass Effect 2, there is a section where you are ambushed while on a floating platform within a Collector ship. While here, several waves of enemies engage you from a few sides starting on nearby platforms that attach to yours. Harbinger frequently "assumes direct control" of Collectors during these fights. The most troubling of these waves is probably the first one because Harbinger starts out very close to your team and you have basically no options to retreat. Thus, the only high-level strategy I can think of is to destroy Harbinger before he closes on my team.

On a difficulty other than the highest (Insanity, I think it is called) destroying him isn't a big deal for any class. However, I really only enjoy ME2 on Insanity. As a soldier, selecting the upgraded assault rifle for your upgrade enables you to do sufficient damage to Harbinger that you can put him down before he reaches you. However, I haven't found a way for any other class to deal enough damage to Harbinger in that short space of time. (This is the only part of the game where I have to tone the difficulty down for other classes.)

Assuming Insanity difficulty, and whatever party/armor/weapon* combination you'd like, how can a non-soldier Shepard and friends defeat Harbinger at this point in the game.

*While I own most of the DLC, I do not own any DLC that only grants weapon packs as they seem to be strictly better than the in-game weapons, and thus I consider using such DLC to be paying money to lower the difficulty (cheating.)