Lots of opportunities to be hating on tupperware and laughing at possible aspects of the behavior of the involved parties.
I want to know a) was the gun in the purse contained by a secure (in any way you want to define that so long as it keeps hold of the gun and keeps purse detritus out of the trigger area) holster? b) Was the secure holster (if it existed) in amongst the rest of the stuff in the purse or was it in a separate compartment?
This incident does not have the hallmarks of a booger hook/bang swithch interface episode. This may in fact be a time that the gun "went off".