[theGeatZhopa]

Equip them with explosive load and make them pursue the shooters like kamikaze drones. That would be effective and with less side effects like with pepper spray & wrong eyes of unrelated /s

And then, you need communicating 3 drones at least. If the shooter decides to run away and run into a room locking the door, then the first drone is making the hole,the second it's job and the third is waiting outside for the shooter who possibly might escape the room.

I see it as natural evolution of this. Weapons can't be forbidden. It's a human right /s

[soco]

Why not putting weapons on the drones themselves? Little ground tanks with revolving turrets spewing bullets (and fire!) in the approximate direction of the shooter and their hostages, now that's a powerful deterrent image, yeehaw!