When you break the glass it will cause hundreds of cracks to appear but the pane will keep its shape for the most part (as it is designed to do). At that point you will have to remove the glass itself. As you do this it will break into many small pieces and slivers that are very sharp and tend to go everywhere. For this reason it is common during vehicle rescues to cover a patient with a sheet or turnout coat if a window must be removed.<br>I know I'm not painting a very good picture here but if you get the chance contact your local FD and ask to observe their next extrication drill. It can be interesting demonstration.<br><br>Chris