This is much more doable and easy with only 2 people on Deadrock.
Player 1 stands on the scaffolding above the vortex.
Player 2 stands down low on the scaffolding next to the vortex.
Slide kick the enemies and the other player grabs them pulling them into the vortex awarding you: TEAM - Not in Kansas, Shocker, and Yoink. (Sometimes Gotcha for the right enemy). Then you add the flail to it and get Team Sadist. So thats 200, 100, and 75 points x2 then another 100 x2 for team sadist.
Lvl ups
Leash Fully Upgraded
Defense/Speed - Fully Upgraded (ignore Power)
PMC fully upgraded.
Flail Gun fully upgraded (ignore charges)
(Taken from 360 guide credit goes to GuyAboveMesucks)