If the holstered pistol is in plain view, then you are guilty of the crime of Affray unless you are at a shooting event or out hunting in a rural environment, or in your place of business or private abode.
If it is holstered and not in plain view, and you do not have a ccw, then you are guilty of unlawful carry of a concealed weapon.
A knifeless multitool seems kinda pointless. You've taken away the most important function of the thing.
Better still, don't go to classrooms or dormitories above the second floor.
I tell you what, if you take hold of my Super Redhawk when the hammer is back and I touch off a round, unless you are wearing welders gloves the bypass at the gap between the cylinder face and the forcing cone will vent enough high pressure gas to cut the palm of your hand like a meat cleaver. I bet you will let go then! It'd be far better to grab that revolver back at the hammer and either keep it from retracting or block it from hitting the firing pin or the primer. Don't even think of grabbing around the barrel end behind the muzzle of a semi-auto or the slide will slice and dice your fingers when the gun gets discharged.
Far better advice would be to find something to wallup the pistol and hand of the shooter with good and hard and fast, deflecting the barrel away, and maybe dislodging it or temporarily disabling the shooter or at least giving yourself enough time to administer another good wallup across his chops. I prefer to grab that shooting hand and raise it above the shooter's head while stepping in with a couple good knee shots to the groin if I am reduced to grappling with him.
Still, the best recommendation I can make is to shoot the MF right between the eyes the moment he steps into view. There's not much question of the outcome then!!! >: )
_________________________
The ultimate result of shielding men from the effects of folly is to fill the world with fools.
-- Herbert Spencer, English Philosopher (1820-1903)