After touch down it departed off the runway at speed
I wonder if the pilot may have been too hasty with full reverse pitch on live engine on touch down? Easy to lose directional control. Similar event to a CASA 212 at Tarawa, Kiribati, many years ago after single engine landing and pilot hauled in full reverse pitch on other engine. Wing severely bent after directional control lost and aircraft hit close-in palm trees on side of airstrip. That's where simulator training is handy as its a bit risky to practice max reverse pitch on touch down on one engine in real life