In the video I link in this story, one of the professors talks about a theory that the FRBs result from a magnetic field phenomenon that may take place on magnetars, sort of an ultra-powerful magnetic star-quake, analog of a phenomenon that's been observed in solar storms on our own Sun.
I don't think the "deep shaft" theory is necessary to get such a powerful pulsing effect. You could also have two super-massive objects orbiting around a common center of mass; one of them functions — by means of its gravitational field — to focus the emissions of the other into a highly focused beam.
The frequency-sweep phenomenon is very interesting because it's fairly hard to produce in nature. To see it at such stupendous power levels and sweep rates is highly thought-provoking, and explains why this phenomenon is getting so much attention.
"Cosmic Jets" -- except this one barely shows up at all at radio frequencies... And, of course, whole galaxies don't whirl around fast enough to present brief, repetitive pulses at a distance...'-)
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Like most everyone else here, I suspect that a magnetar may be a good culprit to blame for this one... '-)