Last week at work, how do I play this?

I'm leaving a toxic environment, I'll spare the details but basically the supervisor is a massive POS and I'm leaving without notice, just going to spring it on her at the last second however they are on holiday this week so I won't be able to see the look on their face. Just wondering how I should go about letting them know and how hard should I work etc, don't wanna get fired before I leave but I want to take the piss as much as possible like they've done to me. Any thoughts