Shelter in place? How about identify the threat and terminate with extreme prejudice?
I guarantee you the SF is moving. It’s the poor saps working there without their constitutional right to carry a weapon that are stuck behind their locked door hoping for the best.
First you have to find them, DM is HUGE. Which is one of the reasons you shelter in place, get the non-participants inside, then anybody outside that isn’t an MP is a bad guy, makes things way easier.