Got a slayer with NB once, but my favorite multikill was a breaker. I was above B at twilight gap. Heavy ammo was coming, so hurled a lightning grenade allllll the way over the the back drop point. Stuck it to the wall right next to the spawn. I got a couple hits, and thought, "meh". Then, kill, kill, kill, kill. I'm just like, wut. Fortunately I had the presence of mind through my stunned stupor to record it. If I can figure it out, I'll try and post it.