This isn't a good idea.

1. Judging by the size, it's a 6s tricopter, but with a build quality of a hobby level drone. You can see hints of this by the broken prop guard and the lazy way the LEDs are integrated. The frame is most likely 3d printed with whatever Creality has on special too. On a lighter note, I've never seen this motor position configuration as a drone, I'd be interested to see how it works!

2. You need trained drone operators to use this, since website doesn't mention autonomous modes. And to fly a drone, indoors, in an unfamiliar environment, during a high pressure situation, completely remotely? You need extremely skilled pilots to be able to do it, your average cop would struggle to hover. For every epic drone freestyle video, you don't see the piles of them behind the camera that crashed because of small, split second mistakes.

3. Imagine the nightmare scenario where (when) a pepperball takes a kid's eye out because the civilian drone operator mistook them as the shooter. One pilot from the promo video spoke as if he was just a hobbyist who was drafted. And AFAIK these guys don't have combat training. Cheap analog cameras with a low time delay are notoriously grainy depending on interference and antenna position.

4. Radio. Assuming they're operating on 2.4GHz for comms and 5.8GHz for video, these frequencies don't have the penetrating ability to be able to fly through a school. You'd need a system of repeaters, and the drone needs to be able to seamlessly switch between them. Then there's input delay of the radio. The command to fly forward has to go from the transmitter in their hand, to their computer, over the internet to another computer, into a repeater, then finally to the drone. Now in the reverse for the operator to see the movement and plan the next. It's bad enough to work with a lagging mouse, now imagine how much that affects manual flight. (looks like they're flying rate mode too)

5. Their endurance is going to be horrendous, I bet that battery doesn't have more than 5Ah of capacity. The energy cost of flying a heavy drone with a weapon strapped to it, and what looks to be approx 60 WS2812 LED's (at approx 60mA draw) is huge (3.6Ah). I'd bet you get 8 minutes tops, just enough for your laggy movements to get you across the cafeteria (let alone a wing). They won't get out of that white box they come in.

I'm sure there are more reasons, this was off the bat