I have been working for a non-profit for 2 years. Until recently I have been a model employee. I recently got a new boss and we did not get along. I recently had a meeting with her and her boss. They read me a list of complaints, many of which I heard for the first time and were boderline false (coming in late...by five minutes when all other staff are that late, accusations of being disrespectful to my boss...she admits to yelling at me at the same time). Also they accused me of fraud, Technically, they may be right (I have to consult our head of training), but everyone else in the company does the exact same thing but is not repremanded or even noticed. At the end of the meeting they suspended me and set up a meeting for monday to discuss if I want to still be with the company and if they will still employ me. My question is if I walk in and immediately hand in my two week notice, can they still fire me afterward saying they had already decided to? I dont think they would have b/c they desperately need help, but if if I take that course, they may retaliate. My company does have a policy that leave is paid upon departure if you give two weeks. I have three weeks built up. Im sure they dont want to pay me that.

if I walk in and immediately hand in my two week notice, can they still fire me afterward saying they had already decided to?

Yes, they can. They can also accept your resignation effective immediately.

They would have to weigh paying out your vacation time with paying for your unemployment - if you quit, you don't get unemployment but if they fire you, you do (assuming that you are not fired for a reason that disqualifies you).