Mercedes' tragic flaw is protectiveness over people she loves. Most of the time her friend doesn't want to hang out with her because she can be boring.
Mercedes thinks she knows best. She thinks her friends are going to drown while they are in the deep end. She ends up canceling the get-together. Her friends start to go off on her and tell her to chill. She wouldn't listen and told them to leave her party.
As she starts cleaning, her friend comes and talk to her. Her friend then tries to calm her down. Mercedes tells her friend that it is best to not have the party because she doesn't wanna be on the watch while someone gets hurt.
Mercedes discovered that she only has one time to live right. She apologizes to her friends and starts to loosen up. She apologized to all of her friends. She allows them to continue to have fun at the party.
Mercedes start to have a little too much. She starts to get in the pool. She then jumps in and start to drown. Her friends starts to give her CPR as they call the paramedic. They try very hard to save her.
The paramedics get there and they are unable to save her. They call her family and plan funeral arrangements. R.I.P. Mercedes. Moral of the story have fun while you are still young and enjoy life.