I'd pick the person.

I could take sterilized roaches. Their power in that their population grows like hell. But 1000 you can kill off and that's settled? Okay, deal. Guess, the first hunt would take a half of them for good.

A person? You obviously can't kill them in most jurisdictions unless you are a LEO. But I'd look forward to reach out and cooperate with them in some way. Idk them and maybe they have cool things to talk about or learn from them. Imagine them blasting an ukulele and being open to teach you. Or just being a good friend material.

I'd probably take both and do bonding with a cellar person over killing bugs.