The x-rays that are emitted from the friction of the "stuff" in the accretion disk outside the event horizon. So they can escape. But think about it a bit more. If they are emitted as x-rays and are close to the event horizon they will have a tough uphill climb in order to get away. They lose energy during the climb out and be red shifted. Yet they still come out as x-rays. Their initial energy had to have been tremendous.
The x-rays that are emitted from the friction of the "stuff" in the accretion disk outside the event horizon. So they can escape. But think about it a bit more. If they are emitted as x-rays and are close to the event horizon they will have a tough uphill climb in order to get away. They lose energy during the climb out and be red shifted. Yet they still come out as x-rays. Their initial energy had to have been tremendous.