That's the thing though you can't "increase your security" against this type of threat.
If someone wants to kill someone else... they're going to do it.
Defend against a short range attack and someone will buy a scope.
Defend against that and someone will crash a drone into your head at 100 MPH.

It's comical to think that the solution to this problem is defending against the threat when the real threat is their own corporate policy that plays with people's lives for profit.