That's the correct fear to have, though. And we all understand "human bad guys with tech" are not extinction-level threats. We understand how their killswitch works, too.
AI will definitely be used to kill people (already used in targeting). But the doom / panic is about an existential threat to our species. It's sci-fi and unwarranted for LLMs.
There are at least a few bad guys in the world whose kill switches do not seem to be working even in the absence of futuristic tech.