What If You are About To Be Fired?

I just read some of the best advice ever, for someone in this situation. Hop on over to US News and read Ask A Manager's Alison Green's advice. For example:

2. Next, drop your ego some more, and go to your manager with your guard down. Tell her that you know she hasn't been happy with your performance and that you'd like her advice on how to improve. This conversation is not about defending yourself, even if you ultimately become convinced she's wrong. This step is simply about hearing what she's saying, correct or not, because even if she's objectively wrong, you need to fully grasp her answer in order to figure out the best step for yourself.