Sorry, but nope. Even that had to be taken into account when accounting for the safety zone.
These fireworks are shot up from mortars. Essentially a tube with a ball (the "payload") and a propelling charge underneath. The safety zone must account for misfires of all kinds, including propelling charges that are too weak to hurl the payload far enough. Which is, essentially, what would happen when it hits something on its way.
If that now happened, i.e. if the "ball" hit the quad, what would have happened is that it either cracked due to the impact (NOT exploded, these things don't have contact fuses...), the quad tumbling down out of control and hitting the ground eventually with the fireworks ball falling apart and not becoming a nice star. Or, if it happened JUST at the moment of detonation of the charge, part of the explosives would have hit the quad (there is no "shell" to speak of, so it's kinda unlikely that something solid would hit the quad) and probably made it crash.
Under no circumstances I could possibly imagine this could have led to fireworks "spuzzing around under the the seats of the audience".