Any suggestions for most efficient way of getting Vermin eliminations?

Been farming camos doing the Terminus Director mode strat, but some guns require getting Vermin eliminations for their special camos. When doing this strat, either 1 Vermin or 1 Parasite will spawn at the start of the each round (though often times neither will spawn), making this a very slow part of the grind

I know the default way would be to just play regular Liberty Falls, but I was wondering if any of you had any alternative methods that would be more efficient?