I don't believe an immediate loss of pressure like I experienced can happen without the tube escaping the confines of the tire. So... unless a pinch flat included tearing a hole in the sidewall through which the tube could escape, the tire would take some time (at least a few seconds) to go flat. My tube came out of the tire and blew it right off of the rim; the sidewalls are still intact and the tire is holding air within its new tube as I type this reply. Besides, I had no indication that I was experiencing a flat tire (and I've had my share) before this happened. There was just a strange, momentary noise and then BLAMMO!