The Motherwell game was a 3-1 win, and that shot was at the start of the second half. As you said, Sproat managed to scramble back to put it out for a corner
The own goal I remember from Miller's time, was when Davie Hayes was chasing back and played a passback to Kyle, who had decided to run out to the edge of the box on the right. The ball went past him, he chased back, the ball hit the far post rebounded back off Kyle and into the goal.