On the hurling of the glass.

As we've seen and will see, Lynn has the unholy urge to insert elements of slapstick comedy into the proceedings; this is why Elly's nose resembles a turnip, it's why we see her honk said nose in a comic fashion and it's even why we have her biting into telephone books. While all these things are, while disturbing to behold, essentially harmless, there's a Three-Stooges-like gag that nobody wants to look at: Elly throwing something heavy at John because she takes an insensitive remark of his the wrong way. Lynn might, if asked, tell us that what we're seeing is what she would have liked to have done, she said the same thing about laughing as she heard her children splashing into a river after she shoved them off a bridge; this tells us that there's a lot of anger behind the lines.