Avi8tor.............What exactly is your point? Trying to prove that that the Q400 is a poor product or that the pilot in question is a bit shaky?
Either way, you are completely off the mark (you did state that you are completely unfamiliar with the Q400, and had you known the pilot you'd be dishing out apologies about now). This is a simply a case of very bad luck: Steering fails as the aircraft vacates the runway onto a taxi way with an angle in excess of what the rudder can handle. Add cold ceramic brakes and you end in the sand.
Speaking of sand..........I believe there's a camel with your name on it. Now be a good boy and go play.