I read the same interview as LIPro, the teflon was stated to impede penetration on vests, but allowed the bullets to "stick" to a tempered glass windshield long enough for it to break without deflecting the bullet. (Just for info, I also have watched actual tests done that demonstrated that an oblique shot with a 7.62 NATO AP round at a modern windshield would shatter the glass, but the bullet would deflect and normally not penetrate into the car's cabin area. Second shots of course were easy.)