Comments by "Rob Fraser" (@krashd) on "Woman Suddenly Surrounded by Sharks" video.

For those wondering why glass shower doors can suddenly explode it is often due to a manufacturing defect or installation damage and will usually happen within the first year of owning the door. Tempered glass has a huge amount of stored energy giving it that famous toughness but that energy is pushing against all four edges of the glass. If any of those edges has a microfracture from either the manufacturing process or from hitting something during installation then it can gradually grow over weeks and months until it eventually just gives way and the whole pane shatters as all the stored energy releases. Oven doors, glass table tops, and even car windows can have this happen (any tempered glass really), but it's more common in shower doors and large glass tables because the larger the pane of glass the stronger it's outer edge needs to be, making that edge very susceptible to tiny chips. It has nothing to do with temperature, although moving most glass objects from one extreme temperature to the other will also shatter them.
5