Here's a car analogy: take driving across an intersection. The hazard here is being involved in a collision, possibly fatally, by crossing traffic. The risk i

Here's a car analogy: take driving across an intersection. The hazard here is being involved in a collision, possibly fatally, by crossing traffic. The risk is the likelihood of a car colliding with us when we cross. We mitigate the risk by requiring the traffic to stop at give way lines and/or installing traffic lights. This is the safety protocol. Would you drive across the intersection through a red light, in violation of the rules? Maybe the risk varies during the day as the traffic level varies, but whatever the time, there's always the chance of a collision if you go through a red light, but almost guaranteed safety if you stop at the red and wait for the green. The same considerations apply to dangerous situations at work, such as this case. The hazard is severe, and the risk is high. You avoid the problem by following the rules and working safely. It doesn't matter that they "weren't even close to critical", the situation should never have had the possibility of occurring in the first place. You don't want to rely on a probably OK, you want absolute certainty or as close to that as you can get, otherwise you're playing the odds and it is only a matter of time until there's a serious accident. That's not how things work in serious settings. Just as you would (I hope) not take the wholly unnecessary risk of running a red light, you wouldn't take unnecessary risks with potentially critical masses of Pu.