For more of a deep dive of the different types of Slingshot rides and how they should be operated and when they are clearly not, Coaster College does a deep dive. I watched this only a few days ago! The video focuses on the modern design of these attractions, but does cover what seems to be the older model of this flat ride.
While the video contains footage of the older style slingshots cords breaking in the lower (locked) position, there is no distributing footage contained in the video.
