Regulators go bad, it's a fact of life and common to every brand, not just Chrysler. The only way the window can fall into the door is if, 1) it comes UNBOLTED from the regulator, jumps off the track, and falls down...in which case it would have shattered because it would have done a free fall and not gone straight down, either. or 2), the cable slipped. There are numerous places it could...out of the motor/pulley (cable ate through the plastic housing on my Ford once), the crimp that connects to the track the window bolts into came off, thus releasing the cable and letting the window fall, or the cable slipped off its grooves on the top and bottom of the regulator assembly where it loops over, giving the thing too much slack and letting it give in to gravity. Only way to find out if it is fixable at home is to try to look in there (good luck) or unbolt the window from the regulator, prop it up with a 2x4 inside the door, and unbolt the regulator assembly and pull it out of the door. If it's as simple as a busted crimp or the cable jumping the top or bottom of the assembly, it can be fixed with a second pair of hands to give you some slack while you force it back over the track, or recrimp and slip the end back into the assembly. If you ate through the motor/pulley/gear whatever...give up. Even if you do straighten out the mess of bent up cable, rewind it on the pulley, get the housing put together in a way that you think the cable won't jump track again, it will.
Worst case scenario you buy a whole new regulator for...say 60 bucks and do the job yourself in an hour.