While a firefighter, they taught us to break the glass at the top so that the falling glass does not fall on to you hand, arm, etc.<br><br>During vehicle extrication class, they suggested punching the window near a corner or edge since the glass will flex less and be easier to break. <br><br>I had the opportunity to break a sliding glass door window once. Used a window punch and reached up to the top of the window and pushed. The punch broke the glass, my hand passed through the window and I ended up cutting my wrist and forearm as my hand and arm passed through and down in an arch. <br><br>Yes, tempered glass breaks in thousands of small peices. Each piece of glass has sharp edges that can cut you. The advantage of tempered is there are no large dagger shapped pieces that can stab or pierce.<br><br>Yes, it is recommended you sweep all the glass from the frame using a heavy gloved hand, a tool handle, etc. Then lay a blanket over the bottom edge to further reduce the possiblity of cuts.<br><br>In a water escape scenairo, I would not take the time to pad the lower edge of the window with a blanket while I escaped. I would wait for the water level inside the car to reach the broken window ledge so the pressure is equalized and then open the door and swin out. Of course, I have had the opportunity to practice this in a non-emergency condition.