Oh yeah, and to elaborate - for a human, of course, killing a human is gonna be worse than killing a cockroach, because we feel more empathy for a human than we do a cockroach, and the worth is pretty much assigned on a sliding scale as to how closely we relate to them (ie., a social mammal is gonna be have more worth than some insect, particularly if that insect is deemed a pest or harmful).
From the cockroaches perspective, I assume that they would regard cockroach life as the most valuable, with humans as just being some marauding nuisance which should be disrupted whenever possible.