What’s a black hole ? Take a mass and compress it very prodigiously, as you do so the gravity of its surface becomes exceedingly strong and there comes a point where its so strong that not even light can escape. So a good way to think about a black hole is that its a region with space itself falling inside the black hole. It is a place in event horizon where space falls faster than light. Inside the black hole, you can imagine light trying to get out point outwards but space itself is falling faster than light therefore it drags light inside the black hole.
So lets imagine we fall through the event horizon, that’s place where space is moving faster than light. We fall deeper down the black hole, but if its a rotating black hole than surely they all do, than the centrifugal force begin to slow us down. Deeper into the black hole there is a place called inner horizon where the flow of space slow us back down to the speed of light. At that point, all the matter or material that fell into the black hole has to pile up. What actually happens as a result of that is; stuff trying to get out; stuff falling in, undergoes tremendous collision and it generates extraordinary amount of energy. At the moment where we hit the inner horizon it is extremely bright, blinding flash of light, that’s what the stuff been waiting there trying to get out, but its just held there within the horizon.