I think there is a 4th category - or maybe a 5th, since someone made “what the heck is going on?” a 4th category.
#5 I would call the “PDS” group. That is short for “Particularly Dangerous Situation”, a term the National Weather Service uses for, typically, a predicted widespread hazardous weather event. (Notably, every one of these I recall has turned out to be a rough ride.) When a PDS is predicted, I don’t panic OR “blow it off” OR “accept it peacefully”: Instead, I go into a heightened state of awareness (almost like a slight adrenaline surge), monitor weather information resources closely, and briskly but not frantically make preparations as seem prudent (this is a few hours out, typically.) If the tornado siren goes off or a warning is posted, it’s to the basement we go, but, still not in a panic. I think there are a few such types here...
Your PDA group, You just described most preppers and a good number of former military officer types who understand the OODA loop when it comes to a plan for adversity. Panic never enters into the mind of a disciplined and prepared leader. First you observe, gathering intel and relevant information about the mission or hazard at hand. Second is to orientate, all scenarios are looked at here including the worst case and best worst case, risk reward calculus is used at this stage. Then the PACE system is used to allocate resources for the plan. Third is to decide, the plan is fully formed and setup for purposeful and decisive action. A course of action is decided, resources are allocated and acquired as needed. A key point of the decide phase is a trigger or mission start is agreed on prior to the hazard presenting itself or go for mission call comes. The predetermined trigger is no longer negotiable after the decision is made. Once this trigger is reached the last step Action, the plan is instituted without hesitation and without additional debate its GO TIME. The plan is executed until it is completed or conditions warrant a new OODA loop to be implemented. No where in this process is room for emotions and it completely squashes normalcy bias every time. The military plans like this preppers should too.
One confirmed case of COVID19 in the wild under 100 miles from my front door triggers immediate action it’s that simple and that definitive. That’s the trigger its no longer negotiable.