While, without that video, I've consider the playing territory to be the lane a bowler in on, seeing that delivery, I'd have to say it was a legal delivery: he threw the ball over the foul line, no matter the cause for the ball going onto the other lane. No one interfered with him. It has to be considered a delivery with zero pins knocked down.
Based on that flow of thought, I'd say a "playing territory" was any area passed the foul line from one side of the house to the other.
Remember, if you're on an end pair, and you fall or walk to the right against the wall AND if you touch the wall past the foul line, it is technically a foul. The foul line is not just at the edge of the lane; it extends, technically, from one side of the house to the other and up each wall at either end.