Here's what happens on monday. Employees A-D will be hand wringing regarding the whole friday killings. Some will even be very vocal about removing guns and tougher laws against Auto-matic weapons. If and when you decide to speak your mind, HR will be on your shit faster than a russian purge.
I might suggest once the AHHHHH of guns begins, you immediately contact HR and ask them to please be X asap. THEN inform everyone you work with while no one is not disturbed or heart broken over the senseless killings. YOU and everyone at work needs to NOT discuss anything that may be construed as POLITICAL.
POLITICS DOES NOT BELONG at work and no need for any hard feelings or possibility of raised voices over the killings. EVERYONE has an opinion and if anyone voices a different one than the majority it might be interpreted as a HOSTILE WORK ENVIRONMENT

Trust me on this, having worked within the state.The flag burners will be out en masse and ANY DIFFERENCE OF OPINION will be taken as an attack on them. Why risk your job over their ignorance. YMMV