> Why would she not plead her case behind her locked door? Pass her ID under the door first, explain the situation, and THEN come out?

Read the article. She explains why in the article.

She was focused on a gun pointed at her and didn't know who it was because they did not announce themselves. This is a result of a well-documented byproduct of human behavior in life-or-death situations, specifically tunnel vision and auditory exclusion.

And side from that, doors don't stop bullets. She could've have been viewed as resisting or argumentative. Talk to any LEO and all they want you to do in such situations is comply with their commands.