Modern firing is something HR departments practice. IT's fast, efficient and uncaring. Often, they tell you your done, escort you to your desk to get your personal stuff and take you to the door. While you were being told, they revoked all your security privileges and locked out all your company computer access.
Since everything is done by computer an angry employee can trash files and delete archives. Most folks would never think about it, but due diligence dictates that you can't take the chance. That's why things often happen fast and key cards stop working etc.
What a world.