Photos surfacing of it being back on terra firma...
http://bit.ly/1i6pA0Q
It appears to be confirmed now that there was no emergency, it was the simple case of mixing up two similarly aligned runways and not bothering to cross-check. Happened before, one not so long ago...
It gives a good indication of the cockpit mindset that after stopping at the end of the runway and realizing their mistake, they attempted to turn a 76 around on the grass...