Always an issue when using cheap and poorly installed inertia dynos. Not necessarily a fault by the dyno operator, if a strap snaps you cant help it, I have had straps let go but on a non-inertia dyno such as mainline or dyno dynamics you can switch off the load and the car is immediately under control.
( inertia dyno uses a massive heavy roller to apply the load to the engine as opposed to modern eddy retarder dynos using an electromagnet to apply load that can be switched on and off easily and quickly)
I will post a link later to a forum that tuners use that has loads of these types of videos.
