[McDyver]

I would still argue that no one ran "out of air" in any of those situations. They panicked and/or ignored their training.

The thing about diving equipment (especially regulators), is that they fail safe, meaning that they fail in a way that allows you to keep breathing.

When a regulator fails, it lets gas go. You can always breathe from it. The cylinder won't empty immediately, so you can get to your next gas source (your buddy, or your next gas switch depth) - cave/mine/wreck excluded.