LLMs are simply computer programs that can accept text input and generate text output. The only "threat" there is if somebody takes the output and decides to link it up to a death ray. And in that case the threat is not the LLM, but somebody deciding to LARP out at being a Bond villain, which granted is a concern - but that's tangential to LLMs. Somebody hooking a death ray up to a chess engine, a dragon in Skyrim, or a cat, would be just as much of a threat, if not more.

The programs are completely deterministic. Given the same RNG seed and state, they will output the exact same thing. If there's a bug or undesired behavior, you can fix it. You can turn off the program whenever you fancy, you can revert to early builds, and so on. There is no possible scenario where an LLM just magically becomes sentient, jumps out of the program, takes over everything, and turns into SHODAN unleashed.