I found his lack of safety-glasses and ballistic shields disturbing, especially given that one of the rotors had already disintegrated.

A piece of 3/4" plywood to stand behind would slow down a lot of lightweight shrapnel.

Alas, one of the few useful things that comes with age and experience is an awareness of consequence...

My biggest worry would be the joint at the bottom (the four bolts visible in the video) giving way because the tension is across the top of the wooden beams. That won't end well because suddenly the winch becomes the projectile.

Also, there's not a huge angle from "where the ball is supposed to go when it fires" to "where he's crouching adding energy to the system".

Yes, that seemed a disaster ready to happen, especially as it was already loaded. He must be very confident of his release system.

I would definitely not watch Colin Furze

I can't stand that guy due to the way it is all presented, it's like watching 'Blippy for adults'.

You obviously haven’t seen the Blippy Harlem shake meme.

It's about the same muzzle energy as a .38 special - definitely not a toy!

So with that in mind, his standing behind the loaded device, was akin to him muzzling himself.

I would think the four rules of firearm safety would apply to supersonic trebuchets.

I would think a prototype supersonic trebuchet would come with a lot more rules than a standard firearm.

They would be much closer to the safety precautions for a prototype firearm, which includes things like being behind a blast shield because there is no safe zone if it fails catastrophically.

I don't even trust that the sides of that thing are safe from shrapnel or the rubber bands whipping parts around. If one side of the machine gave way for some reason, it could absolutely swing sideways. That tiny string at the end is probably going fast enough to slice through skin and veins, and it's concerningly close to neck height.

He should have parked his car off to the side and used the engine block for cover. The paneling of the car will stop minor wood shrapnel, and the engine block should be able to stop any metal pieces that come off. Ballistic barriers would be better, but at least you're not standing there tempting fate with your squishy and easily separable limbs.

It already surpasses the muzzle velocity of many handguns with more flexibility in terms of projectile. I would not want to be on the receiving end of one of these.