You initially don't believe it is a shooting because it is unexpected.
A few observations once your brain realizes it is a real shooting:
Fight or flight kicks in and time slows down.
You don't know who is shooting or why or how well they are armed.
You don't know how many people are shooting.
Regarding this video:
He did not know where the shooter was, but he still entered the store. Once in fight or flight mode, you start controlling your risk at very fast intervals. Instead of being relaxed and making a decision every second or so, you start making life threatening decisions every 0.1 seconds. This is why time seems to slow down. Every decision, every move, etc. could be your last, so you don't want to screw it up.
The person filming was not in fight or flight mode and he was not controlling his risk. Could be for many reasons, but this is what I observe.
A few observations when a shooting starts:
A few observations once your brain realizes it is a real shooting:
Regarding this video:
He did not know where the shooter was, but he still entered the store. Once in fight or flight mode, you start controlling your risk at very fast intervals. Instead of being relaxed and making a decision every second or so, you start making life threatening decisions every 0.1 seconds. This is why time seems to slow down. Every decision, every move, etc. could be your last, so you don't want to screw it up.
The person filming was not in fight or flight mode and he was not controlling his risk. Could be for many reasons, but this is what I observe.
Bystander effect is real.