Yup, the bows were set up to fire sequentially. The levers would have been linked together as one trigger, hence why two bows were set off instead of one. It didn't matter what order Alesha pulled the levers, since they were or more or less the same dumb trigger, and each arrow would be fired in a certain order.

The first mistake wasn't a show stopper, since the "fourth" lever would have triggered the fifth crossbow, but once that misfired there were no arrows left for the intended finish. Shame, it would have been really entertaining.

So the arrows that ended up on the pads around him were the exact same arrows set up to be fired?

did no one notice the protective thing he had below his tshirt, it was very obvious on his stomach, it was like some kevlar pad protecting his chest

Although I didn't notice it, I cannot condemn him for wearing it.

The last arrow(s) I watched it back and you could see the one bounce off to his right as you looked, the one the appeared in the target seemed to come from somewhere else, although that might have been an illusion.
Totally underwhelmed

I wondered this at the time... did they come through from the back of the target.

Feel sorry for him but it was a shambles

ETA: I'm not sure where the ones that come from the bow were supposed to go but I remember seeing something like this before that they cam from the back admittedly that might have been Jonathan Creek

Wasn't the actual concept of the performance flawed, even if it had gone smoothly?

Even if the audience were expected to take his word for it that one was aimed at him, at best the act would have amounted to a man supposedly hoping for the best that someone doesn't randomly fire the wrong crossbow at him.

Yeah, it was a mess. The premise was set up more like a magic trick, and a poor one in the sense we had no reason to believe him about the levers. And then all the arrows fired anyway, and none put him in danger. It was an utter shambles