Probably not exploded, just that the lateral stresses that the rocket is designed for.
Rockets have to withstand a lot of different types of forces (axial, all sorts of vibrational, probably hoop type stresses), but massive lateral shocks aren't really one of them.
Even with minimal fuel, the tanks are still highly pressurized, a loss in hull integrity would result is a rapid depressurization of those tanks. It may not have been a fiery explosion, but I would bet it made a hell of a bang.
Rockets have to withstand a lot of different types of forces (axial, all sorts of vibrational, probably hoop type stresses), but massive lateral shocks aren't really one of them.