When the actor throws the Molotov cocktail, you can see it bouncing off the window. When the camera pans back to the window: It went through it.
The pistol shown in the overview as a "Walther P-38" is in fact a Luger P08. Although being the predecessor of the P-38, both guns have not much in common, except for the 9mm caliber. This is an error made by the editor, since the gun being tested is a Walther.