Are you saying you've seen 8k from someone after 11 waves?
Because that... that's actually rather impressive in a backward sort of way.
I don't think I could score that low even if I actively tried to do so.
Update:
I tried this today. Setup was Bronze (difficulty wasn't specified) and Juggernaut because there's very little on Bronze that I would have to kill to defend myself. Plan was to initiate Siege Pulse for DR, use Hex Shield for defence, and avoid the Turret so it wouldn't score for me. I was carrying a PPR and Reegar but never fired them.
First try: got Ghost/Reapers. I had to melee a couple Marauders and I held the Banshees while the others killed them. Going into W7 I had 3k, going into W11 I had about 6k. I did toss out a turret onto a device and I used the shield to block Cannibal and Ravager fire. Unfortunately, I had forgotten that the shield is specced for pulse and damage, and during W11 I blocked some Cannibals from shooting at me. The stupid bastards all walked into the shield and died. Final score, a shade under 10k.
Second try: Giant Hazard Cerberus. Had to melee a couple Turrets, and unfortunately had to put down the shield to block some Guardians at the EZ during W11. Also I seem to have been awarded some bonus points at extraction. Final score, a shade over 10k.
TL;DR I came close but didn't make it, but with a little practice and respeccing the shield I might manage it. 
Also, my pug teams in both games must have been curious why I walked around reviving them, helped with ojectives, and otherwise just lurked in dark quiet corners. But no one said a word. 