since Dora is not very loyal to her employees.
Really?
Dora tends to consider all her employees friends, especially Hanners and, still to some extent, Faye. Not to mention that when Faye was fired and ended up in hospital, Dora kept Faye on the books long enough that the shop's insurance would cover Faye's medical expenses.
Dora might be abrasive at times, but she is a person who has limits, like every one else. That she reacted in such a way to Faye drinking on the job is the fact that Faye went over that limit. Same with everyone else, if Dora explodes at someone, they've pressed some serious buttons in Dora's psyche.
Faye fucked up, once in the long history of CoD (yes, there were other problems, as usual with Faye, but Dora never indicated that those were grounds for firing), and she was Assistant Manager for a while now. Instead of giving her the chance of cleaning up her act, she's fired on the spot. I consider that disloyal - Dora owes a lot to her, including more business. I know that the hire-and-fire practices are a little different in the US, but still. And keeping her on health insurance for a day or so afterwards? I can't believe that you would lose your health insurance with your job, but if you did, it would be downright barbaric to leave your 'friend' with crippling debt in addition to losing her job, especially if it doesn't change anything for you.
She considers her employees friends? Well, depends. When she hired Hanners, she said it was a bad idea to hire friends, and while there was a joke afterwards, I don't think she considers Penelope a friend (she promoted her based on 'seniority', and without asking her if she wanted the extra responsibility first. And without training her.)
Also, she makes no effort to train her employees beyond basic coffee-making. Tai at least tried to give Marten extra responsibility, to prepare him for a better job.
I'm not saying she's a fundamentally bad person, she just doesn't take care of her employees very well. Which I consider disloyal.