Both air bags "popped"? It almost sounds as if they were inflated to the point where they were ripped off of the vehicle. I know you wouldn't have been able to hear if the compressor didn't shut off since it's impossible to hear from inside the cabin but before fitting the new springs and driving out the garage door just go over all the steps you've taken thus far. Can't explain how or why the compressor would not have shut off but going purely by your description of what you heard, that's what I would check for first.