Not all of them. What happens is that Sidley and Protector McGraw get into a dispute over whether to share the armoury's contents with you. Sidley doesn't want ot share; McGraw does. Sidley turns on McGraw, as do most of the Outcasts except for Olin. They fight each other (and you) and most of them die. Just be sure to grab all the stuff after the door opens because any surviving outcasts will take some of the stuff out of there.
Take everything from the armoury immediately, especially the armour and gauss rifle, but make sure you take all you want as you can't get back in after you leave.
When everyone's dead, they can be looted for some good gear.
If you jump out of the simulation pod and go straight to the armoury and in, you might not hear the argument that kicks off the fight. Killing everyone doesn't matter - there's no further quests here and Olin can only repair armour to 51% anyway.