We're sure they're absolutely PR stunts and bullshit.
An LLM does nothing without being prompted. An LLM only has access to the tools you give it via whatever harness you're interacting with it through. An LLM in an actual sandbox has zero chance to hack anything, especially if it's properly air-gapped, as any responsible person would do with technology they actually think is dangerously powerful.
If their LLMs are behaving badly, that's because their prompts are poorly written, their harnesses are vibe-coded garbage, and their "sandboxes" aren't real sandboxes.