One of the MTA employees on here, I forget who, posted that actually, having the locked car for a mass shooting is considered a safety measure because if the doors stay closed, the shooter can be isolated in the car and only kill the people in the car instead of everyone else on the platform. I know that sounds horribly cold, but in terms of numbers of lives it could save, it is considered a positive.
I wonder if the C/R in today's shooting followed protocol or not in terms of opening the doors at the station, closing, having the T/O move the train, etc. Not looking to blame or point fingers or anything, I'm just genuinely curious about the procedures in these horrible situations.