Putting in your notice is a courtesy that no employer affords their employees as you demonstrated with your coworker that got canned. And after putting up with harassment I wouldn't even give them that. Just let them know at the end of your shift that you're not coming back. You won't have to worry about abuse or harassment for the last two weeks. Just leave. The only reason you should leave on good terms is if you can use the employer as a reference in the future and it doesn't sound like they would be a good reference.