Craziest thing happened

I was just upstairs about 6 pm changing Calvin's diaper. I left Violet downstairs like I always do. She was playing with something in the living room, no biggie. All of a sudden, I hear the LOUDEST crash and a very shrill and terrified scream. I grabbed Calvin and RAN down the stairs to see Violet at the bottom of the stairs just sobbing. I scooped her up and she just clutched me screaming. I still had no idea what made the noise. She wasn't hurt, wasn't bleeding, was perfectly fine, just terrified. I held the kids and walked around the corner and looked to my left. The bathroom mirror had fallen off the wall!!!!!! It shattered onto the sink and broke into a million pieces on the tile floor. Thankfully the bathroom door was closed (all but an inch open) so most of the glass stayed contained, but WOW. What in the world? How does a mirror just fall off the wall? The glue just isn't sticky any more or what? I really do not think Violet did anything to make it fall down. It was just a freak accident, and she was the only one in the vicinity to notice. It was soooo loud!!!! My initial thought was something came crashing through a window and she was pinned. The bathroom door was almost shut and I couldn't open it because a big piece of broken mirror had it wedged closed. I took a deep breath, put the kids in their chairs at the table and strapped them in. I stopped to just look around for a minute to process what had just happened, and got them both something to eat and put on a baby einstein video so they would be happy and distracted while I attempted to clean up the mess. Violet had a big bowl of oatmeal, Calvin had cheerios but threw most of them on the floor. :-/ I put shoes and gloves on, took an empty plastic tub from the garage inside, and put the large glass pieces in it, and swept the small pieces, then went over the whole area with the shop vac. Violet watched me intently and kept telling me the mirror broke. It took me so long to clean up that Violet was whining that she had to go potty and Calvin was an absolute mess and annoyed at everything. I was beginning to reach my breaking point of frustration....so I put Calvin to bed because it was obvious he was just tired. Violet got to stay up a little later. She kept looking at the walls, patting them with both hands, and saying "See? These are OK. They aren't going to fall down. They're OK." I'm so glad this didn't happen when Austin and Renee were here! God has some crazy timing. They just left a couple hours ago. Who knows for how many years or months this mirror's strength on the wall was compromised.