There's "proof" that computers can be safer than humans. Faster reaction times, don't get tired, don't lose focus, can perform computations much faster than humans.
All that goes to show that a computer can make mistakes much faster than humans. You didn’t say anything about how that guarantees the computer only makes safe decisions.
But that's kinda the whole point of AI, isn't it? It's a circular argument, computers currently can't make safe decisions, therefore they will never make safe decisions.