Guns don’t just “go off”. I’m going to go out on a limb here and say that this happened because the firearm’s trigger was uncovered and something got caught in the trigger guard. When she moved the purse, that “something” moved the trigger to the rear thus firing a round.
Ladies, please don’t carry your pistol loose in your purse! I recognize that women’s fashions make it difficult to conceal a decent sized gun while still looking feminine. But you still have to consider the purse as a LAST choice. It’s too easy to leave unattended and thieves will often target your purse in a crime. Both can have disastrous consequences.