Can we talk about the scooter in my kitchen that almost took out a line cook

So last Thursday at our spot on 5th in Portland, a server came flying through the pass on one of those little electric scooters and clipped our fry guy's elbow while he was pulling a basket. He dropped the whole thing and hot oil splashed up his forearm, second degree burns, we had to call it and close early. Turns out the owner thought letting staff ride them inside would speed up food running during the dinner rush, which makes zero sense because our kitchen is maybe 12 feet wide. Now we're down a guy for two weeks and the whole line is scared to move fast. Anyone else seen managers pull stuff like this, and how do you push back without getting fired?