Matter in the accretion disk is not (yet) inside the black hole. It is orbiting, and it can even escape. In fact, some of it must escape for accretion to happen at all: The disk has too much angular momentum to be accreted, and so some material must be ejected, carrying off excess angular momentum, in order for the rest to fall into the hole.

The general idea is that matter in the accretion disk slowly makes its way inward (dependent entirely on how well angular momentum can be transported outward with help from magnetic fields). Once it reaches the innermost stable circular orbit or thereabouts, it plunges toward the black hole rather quickly. This defines the inner edge of the disk, and is somewhat above the event horizon.

Now whether or not the matter ever does fall in is another question, but it's as much a question of semantics as physics.

Matter in the accretion disk is not (yet) inside the black hole. It is orbiting, and it can even escape. In fact, some of it must escape for accretion to happen at all: The disk has too much angular momentum to be accreted, and so some material must be ejected, carrying off excess angular momentum, in order for the rest to fall into the hole.

The general idea is that matter in the accretion disk slowly makes its way inward (dependent entirely on how well angular momentum can be transported outward with help from magnetic fields). Once it reaches the innermost stable circular orbit or thereabouts, it plunges toward the black hole rather quickly. This defines the inner edge of the disk, and is somewhat above the event horizon.

Now whether or not the matter ever does fall in is another question, but it's as much a question of semantics as physics.