if you kill a whamprat that comes into your house, that fucker is impinging into civilization and that frakk is toast. No problem. However, not enough rats were in lukes house, or near his house that he needed his rocket powered hover craft to go look for small animals to kill.
i mean he's abully. In the garbage compactor when he met an animal that could fight back he like just ran away, pissed his pants and cried and shit.