Bulletproof glass stops subsonic bullets and water stops supersonic bullets as demonstrated. So, could a theoretical but probably impractical wall consisting of two bulletproof planes of glass spaced two feet apart and separated by the water filling the void between them stop almost all manner of bullets? This is of course for situations that require you to be visible to the outside without being exposed. I do know that a bullet that managed to pass the first plane of glass would eventually drain out all of the water, but hopefully by that time you would have enough of a clue to move to a more secure location. Imagine a Head of State giving speeches from behind this kind of wall. Also, does the kind of water or even liquid used affect this in any way? And the distance between the planes is flexible if need be (especially try to go as short as possible).