I've always had a healthy respect for this stuff. Like James, I'd find a good/stable place to set the stuff on, gauge it's trajectory (if it was a spinning or aerial device) and then light the fuse and hightail it outta there. I'd also keep a garden hose handy just in case, and if it was dry outside, I'd wet the grass and the garage roof beforehand.
That kid who was the "target" of that video might wind up carrying a facial scar for life; all for a few minutes of cheap and dangerous thrills. I can see his kids asking him someday, "Daddy, where did the scar on your face come from? The war? An industrial accident? A car crash?" And he'd have to answer "No, I got it for, uh, being a dumbass one night."
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