Murray had a huge day, but any RB in the NFL could have made this run.
It was well blocked up front, as the Cowboys 5 Olinemen, full back, and slot WR (which was actually Jason Witten) all got good blocks on a member of the Ram's front 7. That left the two safeties as the only players on the field that could potentially make the tackle. The first ate shit for no apparent reason (0:09 second mark), while the second (which was Mikell) got caught flat footed and Murray blew by him.
I think this play says more about Dallas' ability to block (or the Rams inability to play half way decent defense) than it does about DeMarco Murray.