I'm going to let my boyfriend's car battery die
Why do you want your boyfriend's car battery to die?
I don't want to be with him anymore, so I would let his car battery die.
You shouldn't let your bf's car battery die no matter the situation. That's no way to try and end a relationship.
Damn, hold up a second. I just want to leave but he keeps trying to make me stay. I don't know how to get out of this.
If you want to break up you should tell them directly. Bring others with you and do it in a public setting if you are afraid of making a scene or being in danger.