Not sure what the point would be. Her death was news on TV and they talked about her at the police station - I liked that better.
shareNot everything has to be shown - it's sometimes better to just provoke the viewer's imagination, so your own imagination creates the scene - surely your imagination has better special effects than movies!
shareIt wasn't necessary and if you think about the pacing of The Terminator, Aliens, etc, Jim Cameron was right to have it simply as something mentioned in the news. We didn't need to see it happening again so soon.
shareBetter question is - WHY SHOW it? Why do you think it should be shown?
"Why not" is not a logical question, as negations require no specific motivation. Why aren't you climbing Mount Everest today? This does not require a specific motivation, you just haven't made the positive choice TO climb it, you don't have to make a 'negative choice' for everything you aren't doing, or you will never have time for anything else..
This is why no one makes all the possible 'negative choices', because 'not doing' is the default position of a human being. TO DO something requires a choice and a decision, and thus, motivation - 'not doing' doesn't, because that's default.
Therefore, asking 'why not' is completely ridiculous and illogical, and should possibly be outlawed.