Hypernovae

I'm a bit puzzled with hypernovae.

They are, apparently, SN (Supernovae) that take place with its core exposed during the implosion event. The gravitational energy is very quickly converted to kinetic energy, producing as much as 6000x the luminosity of a typical Type 1a SN.

But, if one drops a bowling ball, it doesn't generate the heat until after it hits the ground. In a hypernovae, all that mass at the core is also falling inward into a BH (blackhole). So doesn't that "impact" energy release occur after the mass has fallen past the EH (Event Horizon)? If so, why is it so bright?

SWAIM? :)