Wrap your head around this....
Marines and Soldiers are taught to run toward the "sounds of chaos" at every instance....except on their own military installation during an active shooter scenario.
Then we expect them to shelter in place.
Do that overseas and you're lucky if your unit members don't pound you to an inch of your life and command doesn't charge you with dereliction of duty/cowardice under fire.
How do we solve the problem of active shooters on base?
I don't know. What I do know is that what we're doing now doesn't help. Maybe a rotating, small (4 man team?) quick reaction force trained and equipped to deal with the issue? Again I don't know but the shelter in place is something for civilian and school kids. Not warriors trained and skilled in combat.
Sidenote: Have you noticed that these shootings have an unusually high body count? Since Clinton's 1992 ban affecting personal weapons on military installations and with ever increasing restrictions coming from the Pentagon, its obvious that military installations are in essence "gun free zones". The nightmare scenario has always been that terrorist would attack a Mall. Unless things change we might wake up to a rampage on a military post by a group of terrorist that ends up gunning down a battalion of service members following the "shelter in place" edict.