There were at least 3 rocket motors stacked up out there. For the non-science types i'll make this simple: rockets are explosions contained enough to point it in a useful direction. Shit goes wrong and goes boom. Hydrazine, which was likely used in on the onboard motor of the payload, a fancy name for the spacecraft, is some nasty shit. So the tank holding the nasty shit just got blown the fuck up. This means the nasty shit is likely all over the place, I would stay back and let it evap, but hey, it's your trip.