I love this animation.
It is the best visual representation of my favorite line in all diving: "It'll probably be fine."
The truth of it is that it will. Probably be fine, that is.
Your regulators probably won't fail. You probably won't get lost. You probably will have enough gas. You probably won't lose visibility. The thousands of things that could go wrong probably won't. The perfect alignment of issues to have a fatality will probably not happen either.
But it might.
Gareth's point in his POST about how the holes in your defenses not only move about, but also open and close is an important one. It goes to the core of how we mitigate; why we train, why we drill, why we do shake-downs and build slow experience, why we need build gear familiarity, etc.
We all have holes in every layer of our defenses. People get complacent, people get forgetful, people are... well... human. We make mistakes on the equipment, procedural, preoperational levels and every other level we touch.
But we can keep those holes small. We can identify their movements and prepare for them. We can do the work to ensure that the likelihood of just the right confluence of events doesn't fucking kill us.
Or we can just trust that there are plenty of layers, and that it always has been before, so it'll probably be fine.