.........shoot him!!!!!"

Based on what you've written in this thread... up to this point.... I fixed it for you .......

"holding a gun" ...... isn't a de facto threat to you.....

"verified active shooting scene..."....... verified, not so much, as the officer was the first responder..... at this time we don't even know that the responding officer knew anyone had been shot.... just that shot(s) were fired.

Don't you have experience and training to draw on that might lead you to consider another course of action ?????....... you keep stating your only course of action is to shoot?

I wonder how many officers who go to sleep at night ..... thankful that they didn't shoot first; even if justified.
I spoke at length with one just this past Saturday.....