Happens so fast. In my years of doing amateur displays. I’ve had three clean my underwear moments. Only one was my fault, learned and all my tubes are now fastened down. The last one was last year on the finale, wired up with silver fast fuse. 40 shells. Something malfunctioned in the shell … tube expanded and with rest blowing off, box blew apart. Luckily or fortunately the low blows all went away from the crowd. And across the street to an open field. No matter how safe you try stuff is going to happen at times. Your playing 500 grams of explosives…
I am a regular Clark Griswald if chit can go wrong it will. No plan ever goes smoothly & usually ends up costing me money.