I tried to follow flip407's guide and never got lucky enough.
This guide is not recommended if you haven't already unlocked some of the bonus LDS levels. The LDS levels only unlocked for me after I'd beaten the game, IIRC.
On the third LDS level, which doesn't seem to have a name, there is a giant alien eyeball monster in the middle of the dancefloor. This alien will, if you don't give it sacrifices, summon large tentacles and attack parts of the map randomly. You'll know when it's about to happen because the eye will turn red. After about three tentacle hits, it will turn white again.Two large groups of people stand near the monster speakers near the beginning. Most other people on the map are sleeping. When police are called, they come in from the right on a hoverboard and shoot at people, so make sure you're not on the right side of the map if police are called.
I actually unlocked this by accident after my third try at this level. Using Katie, I started off by setting off both speaker traps, then picked up a few people and fed them to the eye monster as I waited for them to blow up. Make sure you don't go round either side of the eye towards the speakers or you'll die. The police will be called, and take out a large number of people on the right hand side who were probably all sleeping, then bodybag up the dead. After this, set the trap on the school bus in the upper left and move away from it, picking up sleeping people and feeding them to the eye as you go. As this point, it's pretty easy. If people walk past the eye, you can press Y to feed them to it. With Katie's ability to kick people into sleep, you can easily pick them up and carry them to the eye monster. Just be careful not to be around when they wake up or might kick you down.