>These seem to be unstoppable.

I've read some material lately that would seem to suggest otherwise. That material is not very well supported at the moment. Its also been rumoured that Boeing is putting research into this, but the company denies that.

>I wonder how they get out of a black hole? Or do they? Because the black hole continues attracting things in the surroundings.

Good question. But I think its a nonissue. To me your questions can be rephrased as: does the gravity of an object have an affect on the gravity of an object?

I would suspect no, but I honestly don't know. I'm a newbie when it comes to partcle physics. :-(