First, pls no completely kind NPC xeno infestations. Fuck that. It's a random event, not a random pillow delivery. "Lets people harvest organs without a problem" we shouldn't really let people do this either, those organs are more or less problematic at times considering they let people lay eggs and weeds. It is MEANT to inconvenience the crew. Nah, while we're at it meteors should be made into an aesthetic event and space carp should hug instead of bite and spiders should all just be plushies.
Just don't like xenos? Well, cower in Security or just type in "suicide" into the command bar or just go SSD or some shit. Either someone ends up killing the larva and the event's over or the xenos fight it out with the crew (who sometimes actually manages to destroy them pretty hard if Science is doing their job.)
Second, NPC xenos are stupid. They disappear on death, they just rush after random people and iirc they try to break any window on the way for some reason. No strategy required to kill them at all as long as you have a good gun. They don't even ventcrawl. They don't even lay eggs or plant weeds afaik. Trust me, it's much more fun to fight player controlled xenos, you actually have to put some effort into killing them, a task not so easy to do cuz now they're using human logic.