I have much to learn about situational awareness, but I think my sharpness grows when I am in a crowded environment. It’s probably why I prefer being in quiet natural places, but I should sharpen my senses there, too.
I think that is true of us all, especially in a crowded environment.
Generally, in times of crisis or chaos, I would avoid large crowds.
Be aware of entrances and exits; never have your back to an entrance.
Keep your head on a swivel, noting any inconsistencies or irregularities that you may observe.
The first rule of OODA Loop is to "Observe", then you can evaluate the situation for the second step,
"Orient" yourself as to what possible intelligent reactions you can take without emotional baggage (risk assessment)
See, you have already completed the first of two steps of the four step OODA Loop.
The next step is to make a "Decision" how best to respond to the situation; what makes common sense, without risk.
Then the last step is to Act on your decision - Just .."Do IT".