I believe there is multiple redundancy both in cameras being in multiple places and also delivery mechanisms (local copy + remote stream etc). I'm inclined to believe that there are more mitigations that haven't been told in the post, which is plausible.

Hacking the closed-circuit cameras probably only works in a James Bond movie, since all you have to do is keep that circuit air-gapped to prevent it. I imagine that physical access to the cameras' control system is also guarded.