So, I found the quickest way to deal with this quest is to have the G91 Landshark, G91 Landshark
You get them from engineers or in my case, Blingtron. These nasty little cousins of sharks with lasers deal a whopping 37,500 damage in one hit. Just stand there and let them come to you and beat on you, by the time you can do this quest, you should have decent armor, they only do minor damage anyway.
When you have them all around you, lay down an AoE and then the landshark, it will decimate them all in nearly one shot and your AoE should be good enough to pick up the rest of the health in just a couple seconds.
Now, before you say "but what about other people?", there is an achievement tied to this to defeat 10 of them in 10 seconds, so you may as well do it anyway and get the achievement. Plus, it's funny to watch the entire group get blasted like fishing by dropping dynamite in water :P