1st you need to understand there are three major parts to the clutch in your car. The flywheel, the pressure plate and the friction disk. The pressure plate and flywheel are bolted together and attached to the engine crankshaft. The friction disk sits between the flywheel and pressure plate. When you have the clutch disengaged (foot in on pedal) the pressure plate and flywheel separate allowing the friction disk to spin freely with the input shaft of the transmission. When you are stopped or in neutral, the friction disk can slow down and even stop turning. When you are moving, the input shaft of the transmission, and therefore the friction disk, will turn at whatever the gear ratio and speed of the car dictate. So, if your car is geared such that at 30 MPH in 1st gear, the engine would be at redline, when your car is traveling 60 MPH and your shift into 1st gear, the input shaft and friction disk will now be turning at twice the redline RPM of your engine(with the clutch disengaged). At 70 MPH, I am estimating somewhere around 16,000. That creates a huge centripital force on the friction disk and they can (and do) explode with violent force under these kind of abusive conditions.
Drag racing cars are required to have a "scatter sheild" (the equivalent of a bullet proof vest) wrapped around the bell housing to prevent pieces of an exploding friction disk from killing the driver. I am assuming your car has no scatter shield, so if it blows there is a good chance that pieces will come right through the aluminum bell housing and right through the firewall of the car. You can do the math yourself, but at 16,000 RPM an 8 inch diameter disk will have nearly the same velocity as a 45 caliber hand gun. And the chunks will likely be more massive than the bullet from that gun.
