The four steps that break the panic chain: stop, breathe slowly and deliberately, assess, and only then act. In that order, without exception.
Panic rarely arrives out of nowhere. It grows from a chain of small problems, and each one drives your breathing rate and CO2 up, which raises the stress again — a loop that feeds itself. Underwater, instinct points precisely the wrong way: go up fast while holding your breath, the single most dangerous combination in diving. The four steps break the chain at the only place it can be broken, which is before you act. What makes it a cheat code is that you can rehearse it dry — decide today that your first response to any surprise is three slow breaths rather than a movement. One limitation: stopping only works if your buoyancy is dialled. Sinking while you try to hold position is not a pause, it is a second problem. And the rule replaces no training. It simply buys you the seconds in which you can reach what you were taught.